BKDR_CHCHES.NAK

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users. 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 does not have any propagation routine.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

Arrival Details

This backdoor arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

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

Installation

This backdoor adds the following mutexes to ensure that only one of its copies runs at any one time:

• {generated hash of computer name}

Propagation

This backdoor does not have any propagation routine.

Backdoor Routine

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

• Execute Arbitrary Code

It connects to the following websites to send and receive information:

• http://{BLOCKED}k.{BLOCKED}ist.com/{random}.htm

Information Theft

This backdoor gathers the following data:

• Computer Name
• Kernel32.dll File Version
• Network Proxy Settings
• Network Proxy HTTP
• Network Proxy HTTP port
• Network Proxy FTP
• Network Proxy Auto Configuration
• Windows Credentials

Other Details

This backdoor does the following:

• It uses a word document icon and opens a decoy non-malicious document file ({current malware path and malware name}.docx) during execution in an attempt to hide its execution and avoid suspicion
• It steals Network Proxy Related Information by querying Firefox's prefs.js
• It uses gathered windows credentials to download wpad.dat if prefs.js is not available.