➔
search
✕

TROJ_CRYPWALL.CBQ15A4

November 02, 2015
 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.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

278,946 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Nov 2015

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
34d8a9c = "%System Root%\34d8a9cc\34d8a9cc.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
34d8a9cc = "%User Profile%\Application Data\34d8a9cc.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\software\7BBD975DA225A0B139550242E2D97EF2

HKEY_CURRENT_USER\software\7BBD975DA225A0B139550242E2D97EF2\
022223455799DEEF

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\SystemRestore
DisableSR = "1"

Dropping Routine

This Trojan drops the following files:

  • %System Root%\34d8a9cc\34d8a9cc.exe
  • %User Profile%\Application Data\34d8a9cc.exe
  • %User Startup%\34d8a9cc.exe

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{BLOCKED}r.es
  • http://{BLOCKED}you.us
  • {BLOCKED}5.164.184
  • {BLOCKED}5.24.200
  • {BLOCKED}.19.8
  • {BLOCKED}152.31
  • {BLOCKED}.243.88
  • {BLOCKED}5.16.153
  • {BLOCKED}5.239.17
  • {BLOCKED}22.116
  • {BLOCKED}1.74.68
  • {BLOCKED}.105.18
  • {BLOCKED}.149.47
  • {BLOCKED}4.233.64
  • {BLOCKED}4.180.85
  • {BLOCKED}144.185
  • {BLOCKED}24.37
  • {BLOCKED}.185.76
  • {BLOCKED}.59.28
  • {BLOCKED}21.66
  • {BLOCKED}223.42
  • {BLOCKED}.216.34
  • {BLOCKED}7.153.62

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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

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_CURRENT_USER\software
    • 7BBD975DA225A0B139550242E2D97EF2
  • In HKEY_CURRENT_USER\software\7BBD975DA225A0B139550242E2D97EF2
    • 022223455799DEEF

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • 34d8a9c = "%System Root%\34d8a9cc\34d8a9cc.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • 34d8a9cc = "%User Profile%\Application Data\34d8a9cc.exe"

Step 5

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\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
    • DisableSR = "1"

Step 6

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%\34d8a9cc\34d8a9cc.exe
  • %User Profile%\Application Data\34d8a9cc.exe
  • %User Startup%\34d8a9cc.exe

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_CRYPWALL.CBQ15A4. 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.