Analysis by: Jaime Benigno Reyes
 Modified by: Anthony Joe Melgarejo
 ALIASES:

Trojan:Win32/Sirefef.BC (Microsoft), ZeroAccess (McAfee), Trojan.Win32.Sirefef.bb (v) (Sunbelt), Win.Trojan.Zaccess-788 (ClamAV), W32/ZAccess.AA!tr.bdr (Fortinet), W32/Trojan2.NVVP (exact) (F-Prot), Trojan.Win32.Sirefef (Ikarus), Win32/Sirefef.EV trojan (ESET), Backdoor.ZAccess (VBA32)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

This Trojan may be dropped by other malware.

It is used to load and execute a file.

  TECHNICAL DETAILS

Tipo de compactação: 28,672 bytes
Tipo de arquivo: DLL
Residente na memória: No
Data de recebimento das amostras iniciais: 13 Nov 2013

Arrival Details

This Trojan may be dropped by other malware.

Installation

This Trojan drops the following copies of itself into the affected system:

  • %System Root%\RECYCLER\S-1-5-18\{random}\n
  • %System Root%\$Recycle.Bin\S-1-5-18\{random}\n

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan requires the existence of the following files to properly run:

  • %System Root%\RECYCLER\S-1-5-21-{random GUID}\{random value}\@
  • %System Root%\RECYCLER\S-1-5-18\{random value}\@

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It is used to load and execute the following file:

  • %System Root%\RECYCLER\S-1-5-18\${GUID}\U\80000032.@
  • %System Root%\$Recycle.Bin\S-1-5-18\${GUID}\U\80000032.@

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

  SOLUTION

Mecanismo de varredura mínima: 9.300
Primeiro arquivo padrão VSAPI: 9.524.05
Data do lançamento do primeiro padrão VSAPI: 13 Nov 2012
VSAPI OPR Pattern Version: 9.525.00
VSAPI OPR Pattern veröffentlicht am: 14 Nov 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

Search and delete these files

[ Learn More ]
There may be some 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.
  • Ͽstem RootϿRECYCLER\S-1-5-18\${GUID}\U\80000032.@
  • Ͽstem RootϿ$Recycle.Bin\S-1-5-18\${GUID}\U\80000032.@
  • Ͽstem RootϿRECYCLER\S-1-5-21-{random GUID}\${random value}\@
  • Ͽstem RootϿRECYCLER\S-1-5-18\${random value}\@

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_SIREFEF.AFP. 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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