Analysis by: Roland Marco Dela Paz
 Modified by: Adrian Cofreros
ALIASES:

Backdoor.PHP.PhpShell.by(Kaspersky),PHP/C99Shell.G trojan(NOD32),PHP/C99Shell.B(Panda)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Downloaded from the Internet

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.

  TECHNICAL DETAILS

File Size: Varies
File Type: Other
Memory Resident: No
Initial Samples Received Date: 30 Apr 2014
Payload: Connects to URLs/IPs

Arrival Details

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

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Change file permissions
  • Copy file/folder
  • Delete file
  • Create folder
  • Upload file
  • Download file
  • File system search
  • Connect to MySQL and perform query and dumping
  • Gather system information
  • Send an email
  • List running processes
  • Execute a shell command
  • List files/folders
  • Move a folder

Download Routine

This backdoor downloads an updated copy of itself from the following website(s):

  • http://www.{BLOCKED}hka.ru/poll/fx29sh_update.php

NOTES:

This malware is a PHP script in compromised web servers that wait for a connection from a remote host. Once a connection is established, a remote malicious user may then execute malicious commands that are passed as parameters to HTTP requests.

  SOLUTION

Minimum Scan Engine: 9.700
VSAPI OPR PATTERN File: 7.275.00
VSAPI OPR PATTERN Date: 29 Jul 2010

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

Close all opened browser windows

Step 3

Scan your computer with your Trend Micro product to delete files detected as PHP_SHELLC.SMOD. 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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