PHP_IRCBOT.AHC
Windows 2000, Windows XP, Windows Server 2003

Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This backdoor may be hosted on a website and run when a user accesses the said website.
It executes commands from a remote malicious user, effectively compromising the affected system.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
TECHNICAL DETAILS
5,560 bytes
Script
No
04 Nov 2011
Connects to URLs/IPs, Downloads files
Arrival Details
This backdoor may be hosted on a website and run when a user accesses the said website.
Backdoor Routine
This backdoor opens the following port(s) where it listens for remote commands:
- TCP 6667
It connects to any of the following IRC server(s):
- {BLOCKED}c.{BLOCKED}irc.org
It joins any of the following IRC channel(s):
- #Gurit
- #laknat
It executes the following commands from a remote malicious user:
- Logout connection
- Send emails
- Download files
- Switch server
- Launch UDP and TCP flooding method
- Switch server
Download Routine
This backdoor connects to the following URL(s) to download its configuration file:
- http://{BLOCKED}co.kr/r57.txt
It connects to the following URL(s) to download its component file(s):
- http://{BLOCKED}co.kr/a.jpg
- http://{BLOCKED}co.kr/pitbull.jpg
It saves the files it downloads using the following names:
- /tmp/msdp - detected as BKDR_PERLBOT.SMO
- /tmp/marsudi - detected as BKDR_PERLBOT.SMO
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
NOTES:
It sets the permission of the downloaded file to:
- Full
- Read and Execute
SOLUTION
9.200
8.546.02
04 Nov 2011
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Remove malware files dropped/downloaded by PHP_IRCBOT.AHC
- BKDR_PERLBOT.SMO
Step 3
Close all opened browser windows
Step 4
Scan your computer with your Trend Micro product to delete files detected as PHP_IRCBOT.AHC . If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.
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