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TROJ_PROXY.FH

November 30, 2012
 ALIASES:

TrojanProxy:Win32/Koobface.gen!B (Microsoft); Proxy-Agent.bl (McAfee); Suspicious.BredoLab, Suspicious.MH690 (Symantec); Trojan-Proxy.Win32.Agent.ble (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.1948079 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 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:

14,848 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

30 Nov 2012

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:

  • %System%\dll32.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other System Modifications

This Trojan adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
80:TCP = "80:TCP:*:Enabled:dll32"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
7171:TCP = "7171:TCP:*:Enabled:dll32"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyServer = "http=localhost:7171"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyServer = "http=localhost:7171"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyOverride = "*.local;local"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyOverride = "*.local;local"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = "1"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
ProxyEnable = "1"

Dropping Routine

This Trojan drops the following files:

  • %System Root%\dll32.bat
  • %System%\nfr.assembly

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

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_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 80:TCP = "80:TCP:*:Enabled:dll32"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 7171:TCP = "7171:TCP:*:Enabled:dll32"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyServer = "http=localhost:7171"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyServer = "http=localhost:7171"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyOverride = "*.local;local"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyOverride = "*.local;local"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyEnable = "1"

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings
    • ProxyEnable = "1"

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.
  • %System Root%\dll32.bat
  • %System%\nfr.assembly

Step 5

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