PHP_SHELL.AY

 Analysis by: Rika Joi Gregorio

 ALIASES:

Backdoor:PHP/Rsinsyell.B(Microsoft), Mal/PHPShell-A(Sophos)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit), Linux, UNIX, Mac OS

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

  • 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 does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system.

It does not drop any other file.

  TECHNICAL DETAILS

File Size:

1,878 bytes

File Type:

Other

Initial Samples Received Date:

02 Apr 2013

Payload:

Steals information, Collects system information, Downloads files

Arrival Details

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

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

  • Download Arbitrary Files
  • Perform shell command

Dropping Routine

This backdoor does not drop any other file.

Information Theft

This backdoor gathers the following data:

  • Host Name and URI
  • Security Level
  • Public IP Address
  • Private IP Address

Stolen Information

This backdoor sends the data it gathers to the following email addresses via SMTP:

  • {BLOCKED}unshell@{BLOCKED}l.com

NOTES:

This malware injects itself to the document root directory of the affected web server and appends the following URI:

  • /wp-includes/petx.php

This malware runs on PHP Web Server.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

9.832.05

FIRST VSAPI PATTERN DATE:

02 Apr 2013

VSAPI OPR PATTERN File:

9.833.00

VSAPI OPR PATTERN Date:

03 Apr 2013

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

Scan your computer with your Trend Micro product to delete files detected as PHP_SHELL.AY. 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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