Analysis by: RonJay Kristoffer Caragay
ALIASES:

Backdoor:PHP/Hiebot.E (Microsoft); PHP/IRCBOT.FP (AntiVir); Backdoor.PHP.Pbot.A (BitDefender); PHP/Pbot.B!tr (Fortinet); Backdoor.PHP.Pbot (Ikarus)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites. It may be hosted on a website and run when a user accesses the said website.

It requires its main component to successfully perform its intended routine. This is the Trend Micro detection for files that exhibit certain behaviors. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 22,095 bytes
File Type: Script
Memory Resident: No
Initial Samples Received Date: 24 Oct 2014

Arrival Details

This backdoor arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It may be hosted on a website and run when a user accesses the said website.

Download Routine

This backdoor saves the files it downloads using the following names:

  • {malware path}/var/tmp/lol.txt
  • {malware path}/tmp/lol.txt
  • {malware path}/tmp.txt

Other Details

This backdoor connects to the following possibly malicious URL:

  • http://{BLOCKED}a.com//ams/ambroll/lol.txt

It requires its main component to successfully perform its intended routine.

This is the Trend Micro detection for:

  • PHP scripts in compromised Web servers that wait for a connection from a remote host. Backdoor commands are passed as parameters to HTTP requests.

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine: 9.700

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Close all opened browser windows

Step 4

Search and delete these files

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.  
  • {malware path}/var/tmp/lol.txt
  • {malware path}/tmp/lol.txt
  • {malware path}/tmp.txt

Step 5

Scan your computer with your Trend Micro product to delete files detected as PHP_PBOT.MS. 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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