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PE_DAVS.A

May 28, 2013
 ALIASES:

Virus:Win32/Ravs.A (Microsoft); W32/Davs (McAfee); W32.Davs!inf (Symantec); Virus.Win32.Ravs.a (Kaspersky); LooksLike.Win32.InfectedFile!A (v) (Sunbelt); Win32.Ravs.9 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW


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

  TECHNICAL DETAILS

File Size:

1,537,024 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 May 2012

Arrival Details

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

Other System Modifications

This file infector adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Policies\
Microsoft\Windows NT\Windows File Protection

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows NT\Windows File Protection
SFCDisable = "4"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
SFCDisable = "4"

Dropping Routine

This file infector drops the following files:

  • %Windows%\sysmgr.exe
  • %Windows%\svc.dat
  • %Windows%\conf.dat

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

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

Delete this registry key

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT
    • Windows File Protection

Step 3

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Windows File Protection
    • SFCDisable = "4"

Step 4

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • SFCDisable = "4"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Windows%\sysmgr.exe
  • %Windows%\svc.dat
  • %Windows%\conf.dat

Step 6

Scan your computer with your Trend Micro product to clean files detected as PE_DAVS.A. 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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