Analysis by: Mark Joseph Manahan
ALIASES:

Trojan:Win32/MiniFlame.A (Microsoft), Win32/MiniFlame.A trojan (Eset), Backdoor.Win32.MiniFlame (Ikarus)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet

Dubbed as "Mini Flame", this backdoor has similarities to popular malware families such as PLUGX and POISONIVY, which are linked to targeted attacks.

To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

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

It creates an event.

  TECHNICAL DETAILS

File Size: 75,264 bytes
File Type: DLL
Memory Resident: Yes
Initial Samples Received Date: 16 Oct 2012
Payload: Compromises system security, Connects to URLs/IPs

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.

Installation

This backdoor drops the following files:

  • {All Users' Profiles}\datFE2B.da1
  • {All Users' Profiles}\mstlis.log
  • {All Users' Profiles}\Wnm.tmp

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

  • Global\ShlZoneDataMutex
  • Global\ShlZoneSynchMutex

Backdoor Routine

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

  • Download File
  • Upload File
  • Create process
  • Load modules
  • Manage Registry
  • Invoke sleep command

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • cache.{BLOCKED}s.info/cgi-bin/feed.cgi
  • cache.{BLOCKED}s.info/cgi-bin/feed.cgi
  • web.{BLOCKED}ycache.com/cgi-bin/feed.cgi
  • web.{BLOCKED}lash.info/cgi-bin/feed.cgi
  • webapp.{BLOCKED}tp.com/cgi-bin/feed.cgi
  • webupdate.{BLOCKED}o.org/cgi-bin/feed.cgi
  • {BLOCKED}.{BLOCKED}.49.203
  • cache.{BLOCKED}s.info/cgi-bin/feed.cgi
  • web.{BLOCKED}ycache.com/cgi-bin/feed.cgi

Other Details

This backdoor connects to the following URL(s) to check for an Internet connection:

  • www.google.com

It creates the following event(s):

  • Global\AdvTW32AutoDetect
  • Global\AdvTW32Ready400WfEvent
  • Global\AdvTW32SyncEvent
  • Global\EPOAgentEvent
  • Global\ShellTRPInitEvent
  • Global\TRStepEvent
  • Global\TUSEvent

NOTES:

This backdoor searches for a running process named OUTPOST.EXE and exits when found. It also renames the file icsvnt32a.ocx to icsvnt32.ocx.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.464.04
FIRST VSAPI PATTERN DATE: 16 Oct 2012
VSAPI OPR PATTERN File: 9.465.00
VSAPI OPR PATTERN Date: 17 Oct 2012

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Search and delete these files

[ Learn More ]
There may be some component 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.  
  • {All Users' Profiles}\Wnm.tmp
  • {All Users' Profiles}\datFE2B.da1
  • {All Users' Profiles}\mstlis.log
  • icsvnt32.ocx

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_FLAMER.SMA. 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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