BKDR_IRCBOT.A

October 13, 2012
 ALIASES:

MonitoringTool:Win32/CamServer.B (Microsoft); Generic BackDoor!d2h (McAfee); Backdoor.Trojan (Symantec); PAK:UPX, ARC:BatToExe, PAK:[ip.exe]:UPX, ARC:[ip.exe]:BatToExe, [ip.exe/ip.bat]:Trojan-Spy.BAT.ConnS (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Dropped:Backdoor.Generic.589107 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor 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:

451,584 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Jun 2012

Arrival Details

This backdoor 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 backdoor creates the following folders:

  • %User Temp%\1.tmp
  • %System%\sysfiles
  • %System%\sysfiles\server
  • %User Temp%\2.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
cam_server.exe = "%System%\sysfiles\server\cam_server. exe pass=pawelcom port=57011"

Other System Modifications

This backdoor deletes the following files:

  • %User Temp%\1.tmp
  • %User Temp%\2.tmp
  • %User Temp%\2.tmp\localip.txt
  • %User Temp%\2.tmp\realip.txt

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%System%\sysfiles\server\cam_server.exe = "{random characters}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
57011:TCP = "57011:TCP:*:Enabled:all"

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
SMTP server = "smtp.yandex.ru"

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
SMTP Port = "25"

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
Try = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
Login = "aXAuc2NhbmVyLnBhd2Vs"

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
Pwd = "cGF3ZWxjb20="

HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\
Blat
Sender = "ip.scaner.pawel@yandex.ru"

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\1.tmp\inst.cmd
  • cam_server.exe
  • ip.exe
  • blat.exe
  • blat.lib
  • blat.dll
  • realip.exe
  • %Windows%\Tasks\security.job
  • localip.txt
  • realip.txt
  • %System%\sysfiles\ip.exe
  • %System%\sysfiles\server\cam_server.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.. %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

Restart in Safe Mode

[ Learn More ]

Step 3

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\Public Domain
    • Blat

Step 4

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\Microsoft\Windows\CurrentVersion\Run
    • cam_server.exe = "%System%\sysfiles\server\cam_server. exe pass=pawelcom port=57011"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %System%\sysfiles\server\cam_server.exe = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
    • 57011:TCP = "57011:TCP:*:Enabled:all"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • SMTP server = "smtp.yandex.ru"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • SMTP Port = "25"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • Try = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • Login = "aXAuc2NhbmVyLnBhd2Vs"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • Pwd = "cGF3ZWxjb20="
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Public Domain\Blat
    • Sender = "ip.scaner.pawel@yandex.ru"

Step 5

Search and delete these files

[ Learn More ]
There may be some component files 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%\1.tmp\inst.cmd
  • cam_server.exe
  • ip.exe
  • blat.exe
  • blat.lib
  • blat.dll
  • realip.exe
  • %Windows%\Tasks\security.job
  • localip.txt
  • realip.txt
  • %System%\sysfiles\ip.exe
  • %System%\sysfiles\server\cam_server.exe

Step 6

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%\1.tmp
  • %System%\sysfiles
  • %System%\sysfiles\server
  • %User Temp%\2.tmp

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_IRCBOT.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.

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %User Temp%\1.tmp
  • %User Temp%\2.tmp
  • %User Temp%\2.tmp\localip.txt
  • %User Temp%\2.tmp\realip.txt


Did this description help? Tell us how we did.