TROJ_FAKEAV.NLL

May 07, 2014
 Analysis by: Vincent Martin Hermosura
 ALIASES:

Troj/Agent-ACSN (Sophos), Trojan horse FakeAV_s.AAK (AVG), W32/Kryptik.BG!tr (Fortinet), Trojan.Win32.FakeAV (Ikarus), Rogue:Win32/FakeRean (Microsoft), FakeRean-FAD!E0214180868A (NAI), a variant of Win32/Kryptik.BGQI trojan (Nod32), Trojan.Win32.Encpk.akt (v) (Sunbelt), TR/Crypt.XPACK.Gen2 (Antivir),

 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:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

840,192 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Aug 2013

Arrival Details

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

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Internet Security = "{malware path}\{malware file name}.exe"

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\{random}
FRun = "0"

HKEY_CURRENT_USER\Software\{random}
O`ld = "Houdsodu!Rdbtshux"

HKEY_CURRENT_USER\Software\{random}
Q`ui = "{random}"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}ersecurityauto.com/buynow.php?bid=233

  SOLUTION

Minimum Scan Engine:

9.700

Step 1

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Internet Security = "{malware path}\{malware file name}.exe"

Step 3

The following created registry key(s) cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:

    HKEY_CURRENT_USER\Software\{random}

Step 4

Scan your computer with your Trend Micro product to delete files detected as TROJ_FAKEAV.NLL. 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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