PHP_CRYPWEB.A

February 07, 2015
 Analysis by: Francis Xavier Antazo
 ALIASES:

PHP/Webcoder.A trojan (NOD32), PHP.Ransomcrypt.A (NORTON_BETA),

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may arrive bundled with malware packages as a malware component. It 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.

  TECHNICAL DETAILS

File Size:

798 bytes

File Type:

Script

Memory Resident:

No

Initial Samples Received Date:

03 Feb 2015

Arrival Details

This Trojan may arrive bundled with malware packages as a malware component.

It 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.

Other Details

This Trojan requires the following additional components to properly run:

  • factory.php
  • functions_user.php
  • ucp_activate,php
  • ucp_profile.php

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

NOTES:

It connects to the following URL to download the contents of the file that will be used to compute for its crypt key

  • http://{BLOCKED}3.{BLOCKED}3.120.108/sfdoif89d7sf8d979dfgf/sdfds90f8d9s0f8d0f89.txt

It modifies the following file to allow encryption

  • ../config.php

It retrieves all the entries for the following database table

  • USERS_TABLE (phpbb framework constant)

It encrypts the following variables for every entry in the database search result

  • user_password
  • user_email

It drops copies of the following files (source) into the following destination paths (dest)

(source)

  • factory.php
  • functions_user.php
  • ucp_activate.php
  • ucp_profile.php

(dest)

  • ../phpbb/db/driver/factory.php
  • ../includes/functions_user.php
  • ../includes/ucp/ucp_activate.php
  • ../includes/ucp/ucp_profile.php

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

11.456.05

FIRST VSAPI PATTERN DATE:

03 Feb 2015

VSAPI OPR PATTERN File:

11.457.00

VSAPI OPR PATTERN Date:

04 Feb 2015

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_CRYPWEB.A. 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.

NOTES:
Restore the encrypted files from backup.


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