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Randex.Q

Classification

Category: Malware

Type: -

Aliases: Randex.Q, W32.Randex.Q, W32/Randex.Q, Worm.Randex.Q, Backdoor.SDBot.gen

Summary


Randex (also known as SDBot) is a backdoor with network worm capabilities. This variant of Randex appeared on 28th of November 2003. It is functionally similar to previous versions, but has less features.

Removal


Automatic action

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Technical Details


The backdoor's file is a Windows PE executable 37376 bytes long. It is compressed with patched UPX file compressor.

When activated, the backdoor gets API addresses of different Windows functions and checks whether it is already installed on this computer. If not, the backdoor copies its file as 'msrundll.exe' to Windows System directory and creates a startup key for it in the Registry:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
"Microsoft Windows Kernel Functionalities" = "msrundll.exe"
[HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices]
 "Microsoft Windows Kernel Functionalities" = "msrundll.exe"

After the backdoor starts, it tries to connect to an IRC server (one hardcoded name) and creates a bot in the specific channel (hardcoded name) on this server. Through this bot a hacker can control the backdoor's behaviour. A hacker can perform the following actions:

1. Log in and out of the bot (requires a password)
2. Terminate own process
3. Generate another random nickname for the bot
4. Connect, reconnect and disconnect from IRC server
5. Show bot status
6. Show bot ID
7. Show threads list
8. Show aliases list
9. Show log file
10. Start and stop sniffer functionality
11. Show network info
12. Show system information
13. Start and stop NTScan (spread to network)
14. Remove the bot
15. Delete the PAYLOAD,DAT file
16. Change bot's nickname
17. Join/part channels
18. Kill specific threads
19. Send SYN packets
20. Add aliases
21. Send private messages
22. Change channel mode
23. Join/part specific channel in a cycle
24. Update the backdoor
25. Start a specific file
26. Create clones
27. Download files
28. Show infected computer's IP address and connection type
 

When instructed to do a NTScan, the backdoor copies itself to Windows System folder as 'ms093upd.dat', generates random IP addresses and tries to connect to them. The backdoor tries to retrieve network user names and connect using them, but in case this fails, it will try to connect as Administrator.

The backdoor uses the following passwords to connect to remote computers:

admin
root
1
111
123
1234
123456
654321
!@#$
asdf
asdfgh
!@#$%
!@#$%^
!@#$%^&
!@#$%^&*
Guest
Gast
Administrateur
server
Administrator
Beheerder
super
user
password
secret
xp
nt
me
love
girl
iloveyou
tits
pussy
2600
2800
hacker
leet
l337
 

Once connected the backdoor tries to access to IPC$ share on remote computer and to copy itself to the following locations as 'MSL32.exe' and 'MSL3232.exe' files:

\Admin$\system32\MSL32.exe
\c$\winnt\system32\MSL3232.exe
 

The above locations correspond to System32 folders of NT-based operating systems.

After copying its file, the backdoor creates a scheduled network task to start the copied infected file on remote computer. When this happens, a remote computer becomes infected with the backdoor.

F-Secure Anti-Virus already detects this worm generically as 'Backdoor.SDBot.gen'.