TROJ_PERLBOT.A


 PLATFORM:

Windows

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

  • 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:

4,754,944 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

01 Sep 2016

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.

Installation

This Trojan creates the following folders:

  • %User Temp%\pdk-Wilbert
  • %User Temp%\pdk-Wilbert\9005e7c09178ffafdbb3ee438b3368cc
  • %User Temp%\pdk-Wilbert\8c95bdd9ed7e62349109c64a0c85a8e3
  • %User Temp%\pdk-Wilbert\223a673a9d7919bfe5b74eab39572f80
  • %User Temp%\pdk-Wilbert\73df8010ad1afc8d6d1d2ac046fb9ac9
  • %User Temp%\pdk-Wilbert\e70306afd542b14dcdac2a0457bec6d9
  • %User Temp%\pdk-Wilbert\8df557864b35fe1e721d12677c17b558
  • %User Temp%\pdk-Wilbert\7372e1dfb6412e49ebbd97590102280d
  • %User Temp%\pdk-Wilbert\c7267d42b437d0423f84c3f26148e6e7
  • %User Temp%\pdk-Wilbert\77505471dd2d8b33c3a6204f1531295b
  • %User Temp%\pdk-Wilbert\b54c3c8babc3e43389d9bbd280333cdd
  • %User Temp%\pdk-Wilbert\b1638e4486293fcce84c3ca41316ab59

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = "0"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Lsa
Security Packages = "kerberos wdigest msv1_0 schannel tspkg pku2u"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\pdk-Wilbert\9005e7c09178ffafdbb3ee438b3368cc\perl522.dll
  • %User Temp%\pdk-Wilbert\8c95bdd9ed7e62349109c64a0c85a8e3\Fcntl.dll
  • %User Temp%\pdk-Wilbert\223a673a9d7919bfe5b74eab39572f80\Storable.dll
  • %User Temp%\pdk-Wilbert\73df8010ad1afc8d6d1d2ac046fb9ac9\Encode.dll
  • %User Temp%\pdk-Wilbert\e70306afd542b14dcdac2a0457bec6d9\Win32.dll
  • %User Temp%\pdk-Wilbert\8df557864b35fe1e721d12677c17b558\Daemon.dll
  • %User Temp%\pdk-Wilbert\7372e1dfb6412e49ebbd97590102280d\Util.dll
  • %User Temp%\pdk-Wilbert\c7267d42b437d0423f84c3f26148e6e7\API.dll
  • %User Temp%\pdk-Wilbert\77505471dd2d8b33c3a6204f1531295b\IO.dll
  • %User Temp%\pdk-Wilbert\b54c3c8babc3e43389d9bbd280333cdd\Socket.dll
  • %User Temp%\pdk-Wilbert\b1638e4486293fcce84c3ca41316ab59\POSIX.dll

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}9.69.25

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.8

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 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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • EnableBalloonTips = "0"

Step 3

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\SYSTEM\ControlSet001\Control\Lsa
    • From: Security Packages = "kerberos wdigest msv1_0 schannel tspkg pku2u"
      To: Security Packages = ""{random values}""

Step 4

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.
  • %User Temp%\pdk-Wilbert\9005e7c09178ffafdbb3ee438b3368cc\perl522.dll
  • %User Temp%\pdk-Wilbert\8c95bdd9ed7e62349109c64a0c85a8e3\Fcntl.dll
  • %User Temp%\pdk-Wilbert\223a673a9d7919bfe5b74eab39572f80\Storable.dll
  • %User Temp%\pdk-Wilbert\73df8010ad1afc8d6d1d2ac046fb9ac9\Encode.dll
  • %User Temp%\pdk-Wilbert\e70306afd542b14dcdac2a0457bec6d9\Win32.dll
  • %User Temp%\pdk-Wilbert\8df557864b35fe1e721d12677c17b558\Daemon.dll
  • %User Temp%\pdk-Wilbert\7372e1dfb6412e49ebbd97590102280d\Util.dll
  • %User Temp%\pdk-Wilbert\c7267d42b437d0423f84c3f26148e6e7\API.dll
  • %User Temp%\pdk-Wilbert\77505471dd2d8b33c3a6204f1531295b\IO.dll
  • %User Temp%\pdk-Wilbert\b54c3c8babc3e43389d9bbd280333cdd\Socket.dll
  • %User Temp%\pdk-Wilbert\b1638e4486293fcce84c3ca41316ab59\POSIX.dll

Step 5

Search and delete these folders

[ 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.
  • %User Temp%\pdk-Wilbert
  • %User Temp%\pdk-Wilbert\9005e7c09178ffafdbb3ee438b3368cc
  • %User Temp%\pdk-Wilbert\8c95bdd9ed7e62349109c64a0c85a8e3
  • %User Temp%\pdk-Wilbert\223a673a9d7919bfe5b74eab39572f80
  • %User Temp%\pdk-Wilbert\73df8010ad1afc8d6d1d2ac046fb9ac9
  • %User Temp%\pdk-Wilbert\e70306afd542b14dcdac2a0457bec6d9
  • %User Temp%\pdk-Wilbert\8df557864b35fe1e721d12677c17b558
  • %User Temp%\pdk-Wilbert\7372e1dfb6412e49ebbd97590102280d
  • %User Temp%\pdk-Wilbert\c7267d42b437d0423f84c3f26148e6e7
  • %User Temp%\pdk-Wilbert\77505471dd2d8b33c3a6204f1531295b
  • %User Temp%\pdk-Wilbert\b54c3c8babc3e43389d9bbd280333cdd
  • %User Temp%\pdk-Wilbert\b1638e4486293fcce84c3ca41316ab59

Step 6

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


Did this description help? Tell us how we did.