Analysis by: Anthony Joe Melgarejo
 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

Infection Channel: Downloaded from the Internet

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.

It adds accounts to have an administrator privilege. This allows the malware or a malicious user to perform tasks that may put the affected system in greater risk.

  TECHNICAL DETAILS

File Size: 3,757 bytes
File Type: Other
Initial Samples Received Date: 15 Nov 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.

Installation

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

  • {AutoCad working directory}\acaddoc.fas

It drops the following files:

  • {malware path}\acad.reg

Other System Modifications

This Trojan deletes the following files:

  • acaddoc.lsp

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
ServicesTlntSvr
Start = "2"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon\
SpecialAccounts\UserList
servicer = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\Lsa
forceguest = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
UserAssist\{75048700-EF1F-11D0-9888-006097DEACF9}\Count
HRZR_EHAPCY = "0C 00 00 00 26 00 00 00 F0 FB E5 52 64 95 C6 01"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
UserAssist\{75048700-EF1F-11D0-9888-006097DEACF9}\Count
HRZR_EHAPCY:"P:\JVAQBJF\flfgrz32\sverjnyy.pcy",Jvaqbjf = "0C 00 00 00 08 00 00 00 F0 FB E5 52 64 95 C6 01"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Epoch
Epoch = "1ED"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Print\Providers
LogonTime = "E8 31 8E 4F 64 95 C6 01"

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
445:TCP = "445:TCP:LocalSubNet:Enabled:@xpsp2res.dll,-22005"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
137:UDP = "137:UDP:LocalSubNet:Enabled:@xpsp2res.dll,-22001"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
138:UDP = "138:UDP:LocalSubNet:Enabled:@xpsp2res.dll,-22002"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
139:TCP = "139:TCP:LocalSubNet:Enabled:@xpsp2res.dll,-22004"

Other Details

This Trojan adds the following accounts to the Administrator group:

  • servicer

NOTES:

This malware creates the following network shares to the corresponding drives:

  • C$=C:\
  • d$=d:\
  • e$=e:\
  • f$=f:\
  • g$=g:\
  • h$=h:\
  • i$=i:\

It sets the following flags as the properties for the added user account:

  • ADS_UF_SCRIPT
  • ADS_UF_NORMAL_ACCOUNT
  • ADS_UF_DONT_EXPIRE_PASSWD

Once a new drawing file is opened, the dropped copy is automatically loaded and executed.

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 9.962.06
FIRST VSAPI PATTERN DATE: 05 Jun 2013
VSAPI OPR PATTERN File: 9.963.00
VSAPI OPR PATTERN Date: 05 Jun 2013

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

Scan your computer with your Trend Micro product and note files detected as ACM_SHENZ.A

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\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 445:TCP = "445:TCP:LocalSubNet:Enabled:@xpsp2res.dll,-22005"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 137:UDP = "137:UDP:LocalSubNet:Enabled:@xpsp2res.dll,-22001"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 138:UDP = "138:UDP:LocalSubNet:Enabled:@xpsp2res.dll,-22002"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 139:TCP = "139:TCP:LocalSubNet:Enabled:@xpsp2res.dll,-22004"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ServicesTlntSvr
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList
    • servicer = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
    • forceguest = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\{75048700-EF1F-11D0-9888-006097DEACF9}\Count
    • HRZR_EHAPCY = "0C 00 00 00 26 00 00 00 F0 FB E5 52 64 95 C6 01"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\{75048700-EF1F-11D0-9888-006097DEACF9}\Count
    • HRZR_EHAPCY:"P:\JVAQBJF\flfgrz32\sverjnyy.pcy",Jvaqbjf = "0C 00 00 00 08 00 00 00 F0 FB E5 52 64 95 C6 01"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Epoch
    • Epoch = "1ED"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Print\Providers
    • LogonTime = "E8 31 8E 4F 64 95 C6 01"

Step 4

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

NOTES:

Step 3

To delete the user account this malware created:

  1. Open Command Prompt. Click Start>Run, type CMD, then press Enter.
  2. In the Command Prompt window, type net user servicer /delete, then press Enter.

Step 4

To delete the network shares this malware created:

  1. Still in the Command Prompt window, type net share C$ /delete, then press Enter.
    (Note: For the following steps, you can skip the steps if the network share to be deleted is actually shared in your system before infection.)
  2. In the Command Prompt window, type net share D$ /delete, then press Enter.
  3. In the Command Prompt window, type net share E$ /delete, then press Enter.
  4. In the Command Prompt window, type net share F$ /delete, then press Enter.
  5. In the Command Prompt window, type net share G$ /delete, then press Enter.
  6. In the Command Prompt window, type net share H$ /delete, then press Enter.
  7. In the Command Prompt window, type net share I$ /delete, then press Enter.
  8. Type exit to close the Command Prompt window.


Did this description help? Tell us how we did.