Errors running "UNIX-System V" ELF executables [I've been hacked!]

[Dan S.]

Hello to all,

Hopefully someone can help me progress past a pair of "ELF Binary Type 0 not
known"  & "ELF Interpreter /compat/linux/lib/ld-linux.so.2 not found"
errors.

Here is the background & problem, bullet point style:

-  I unfortunately had a hosted & jailed virtual server running FreeBSD
4.6.2 get broken into via a user account with a weak password. The intruder
installed at least two binaries: /tmp/" "/miro (almost certainly a
rootkit/backdoor) and /home/$hackeduser/" "/psybnc/psybnc (an IRC proxy).
(Yes, this is a creaky old OS; I've been letting it sit
dormant/mostly-unused and this is the price I pay for my lax sysadminning.)

- The hosts were kind enough to provide me with a dump of the jailed server;
I've now got a fairly minimal install of 4.6.2-RELEASE running under QEMU
and, inside that, a jail for the image from the hosting providers.

- The 'psybnc' binary definitely ran on the hosted virtual server; it
creates a log file and its timestamp & contents were recent. I don't know if
the 'miro' rootkit was successful or not. I'm crossing my fingers that it
wasn't, and trying to investigate a bit what it does. "kldstat" on the
hosted server didn't show any compatibility files up. (In particular, no '
linux.ko'; I have loaded that module on the qemu version to see if I could
get further.)

- In my qemu freeBSD, under the jail, neither program runs either as root or
as the hacked user:
  - $HOME/" "/psybnc/psybnc ----> 'ELF binary type "0" not known.' (note:
this is with 'linux.ko' loaded)
  - /tmp/" "/miro        ---> "ELF interpreter /compat/linux/lib/ld-
linux.so.2 not found"
  - /tmp/" "/miro, If I unload linux.ko :  ----> 'ELF binary type "0" not
known."

- Oddly, both have the exact same (except for offsets) elf headers:

----- readelf -h /tmp/" "/miro  ---------
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x8048b10
  Start of program headers:          52 (bytes into file)
  Start of section headers:          16944 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         6
  Size of section headers:           40 (bytes)
  Number of section headers:         30
  Section header string table index: 27

----- readelf -h $HOME/" "/psybnc/psybnc ------
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           Intel 80386
  Version:                           0x1
  Entry point address:               0x8048100
  Start of program headers:          52 (bytes into file)
  Start of section headers:          1295400 (bytes into file)
  Flags:                             0x0
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         4
  Size of section headers:           40 (bytes)
  Number of section headers:         22
  Section header string table index: 21

=======================

Any advice on how to try and get these to run? I'm really hoping to find out
if the system as a whole was compromised by the rootkit. The user-acount
breakin isn't a huge deal but if more was compromised it will be quite bad.

I'm also happy to send the rootkit/backdoor to anyone who wants to poke at
it. It contains the string: ".-= Backdoor made by Mironov =-."

Thanks to all!
-- Dan S.