Analysis by: Christopher Daniel So
ALIASES:

Worm:Win32/Renocide.gen!A (Microsoft), W32.Harakit (Symantec), W32/Autorun.worm.zf.gen (McAfee), Worm.Win32.AutoIt.xl (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 632,820 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 25 Jul 2011

Arrival Details

This worm 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 copies of itself into the affected system:

  • %System%\csrcs.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It drops the following files:

  • %System%\autorun.inf
  • %System Root%\rfbu
  • %User Temp%\{random file name 1}
  • %User Temp%\{random file name 2}

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.)

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
csrcs = "%System%\csrcs.exe"

It modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Shell = "Explorer.exe csrcs.exe"

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

Other System Modifications

This worm deletes the following files:

  • %System%\$winnt$.inf
  • %System%\-1
  • %System%\12520437.cpx
  • %System%\12520850.cpx
  • %System%\6to4svc.dll
  • %System%\aaaamon.dll
  • %System%\aaclient.dll
  • %System%\access.cpl
  • %System%\acctres.dll
  • %System%\accwiz.exe
  • %System%\acelpdec.ax
  • %System%\acledit.dll
  • %System%\aclui.dll

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
DRM\amty

Other Details

This worm connects to the following possibly malicious URL:

  • http://{BLOCKED}ix.{BLOCKED}uster.com:4900/po.php
  • http://www.{BLOCKED}smyip.com/automation/n09230945.asp
  • http://{BLOCKED}eckip.{BLOCKED}ndns.org/?rnd1={random number 1}&rnd2={random number 2}
  • http://{BLOCKED}ix.{BLOCKED}uster.com:4900/banner.gif
  • http://{BLOCKED}gru.fam.cx:5200/ads.php
  • http://{BLOCKED}ratebay.org/top/401

It deletes the initially executed copy of itself