Modified by: Jasen Sumalapao
ALIASES:

Worm:Win32/Chiviper.C (Microsoft), Trojan.Gen.2 (Symantec), Downloader.a!cmx (NAI), Trojan.Generic.KDV.723881 (FSecure), Trojan.Win32.Generic!BT (Sunbelt), WORM/Rbot.Gen (Antivir), Trojan.Generic.KDV.723881 (Bitdefender), W32/Downloader_a.CMX!tr (Fortinet), Trojan-Downloader.Win32.Small (Ikarus), a variant of Win32/PSW.OnLineGames.QDL trojan (NOD32), Generic (Panda)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware, Downloaded from the Internet, Propagates via removable drives

This worm arrives by connecting affected removable drives to a system. 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 adds registry entries to trick a user into thinking that the files it drops are legitimate.

It retrieves specific information from the affected system.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 47,104 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 18 Sep 2012
Payload: Steals information, Downloads files

Arrival Details

This worm arrives by connecting affected removable drives to a system.

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 worm drops the following component file(s):

  • %Windows%\usp10.dll - detected as WORM_CHIVIPER.AA

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It adds the following registry entries to trick a user into thinking that the files it drops are legitimate:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Session Manager
ExcludeFromKnownDlls = usp10.dll

(Note: The default value data of the said registry entry is "".)

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

  • WinSDK32

Other System Modifications

This worm modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = 2

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = 1

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden
Type = group

(Note: The default value data of the said registry entry is "".)

Download Routine

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

  • http://{BLOCKED}f.info/duqu/m97.txt

It saves the files it downloads using the following names:

  • %User Temp%\{random filename}.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Information Theft

This worm retrieves the following information from the affected system:

  • MAC address
  • IP address
  • Operating System
  • Current UserName

Stolen Information

This worm sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}5.xcnowkfla.com/tj1/post.asp

Other Details

This worm deletes itself after execution.

NOTES:

This worm drops copies of itself in all folders on fixed drives and removable drives containing .EXE files. This allows this worm to be loaded when an .EXE file attempts to load the legitimate USP10.DLL.

This happens when an .EXE file loads DLL components from the same folder before checking in the system folders for the component DLL.

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.404.02
FIRST VSAPI PATTERN DATE: 18 Sep 2012
VSAPI OPR PATTERN File: 9.405.00
VSAPI OPR PATTERN Date: 19 Sep 2012

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 and note files detected as WORM_CHIVIPER.AA

Step 3

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete files detected as WORM_CHIVIPER.AA

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden = "2"
      To: Hidden = 1
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = 0
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden
    • From: Type = "group"
      To: Type = ""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
    • From: ExcludeFromKnownDlls = usp10.dll
      To: ExcludeFromKnownDlls = ""

Step 6

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