This backdoor is a variant of the malware family BLYPT. It uses binary large objects (BLOB) to store information in the affected system's registry. It also utilizes encryption. Users affected by this malware may find the security of their systems compromised.
To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.
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.
It executes commands from a remote malicious user, effectively compromising the affected system.
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.
Other System Modifications
This backdoor adds the following registry entries as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
SystemCertificates\CA\Certificates\
5A82739996ED9EBA18F1BBCDCCA62D2C1D670C
Blob = "{Encrypted configuration data}"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download and execute the main backdoor component
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}lution134.org:80
- {BLOCKED}.{BLOCKED}.162.47:81
- {BLOCKED}.{BLOCKED}.162.45:81
- {BLOCKED}.{BLOCKED}.181.50:81
- {BLOCKED}.{BLOCKED}.186.14:778
- {BLOCKED}.{BLOCKED}.186.9:777
- {BLOCKED}.{BLOCKED}.186.27:777
- {BLOCKED}.{BLOCKED}.121.141:777
- {BLOCKED}.{BLOCKED}.97.02:777
- {BLOCKED}.{BLOCKED}.186.47:81
- {BLOCKED}.{BLOCKED}.186.45:81
Download Routine
This backdoor saves the files it downloads using the following names:
- %Application Data%\Microsoft\Crypto\NTCRYPT{variable}.TPL
- %Application Data%\Microsoft\Crypto\CERTV{variable}.TPL
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
Trend Micro detects the dowloaded file as:
- BKDR_BLYPT.B
- BKDR64_BLYPT.B
- BKDR_BLYPT.SM
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
Remove malware/grayware files dropped/downloaded by BKDR_BLYPT.A
Step 3
Scan your computer with your Trend Micro product and note files detected as BKDR_BLYPT.A
Step 4
Restart in Safe Mode
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To restart in Safe Mode:
• For Windows 2000 users
- Restart your computer.
- Press F8 when you see the Starting Windows bar at the bottom of the screen.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows XP users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Windows Advanced Options menu does not appear, try restarting then pressing F8 several times when the POST screen appears.
- Choose the Safe Mode option from the Windows Advanced Options menu then press Enter.
• For Windows Server 2003 users
- Restart your computer.
- Press F8 after Windows starts up. If the Windows Advanced Options menu does not appear, try restarting again and pressing F8 several times afterward.
- On the Windows Advanced Option menu, use the arrow keys to select Safe Mode then press Enter.
• For Windows Vista and Windows 7 users
- Restart your computer.
- Press F8 after the Power-On Self Test (POST) routine is done. If the Advanced Boot Options menu does not appear, try restarting and then pressing F8 several times after the POST screen is displayed.
- On the Advanced Boot Options menu, use the arrow keys to select the Safe Mode option, and then press Enter.
Step 5
Search and delete files detected as BKDR_BLYPT.A
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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.
To delete malware/grayware files:
For Windows 2000, Windows XP, and Windows Server 2003:
- Right-click Start then click Search....
- In the Named input box, type the name of the file that was detected earlier.
- In the Look In drop-down list, select My Computer then press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat steps 2-4 for the remaining files.
For Windows Vista and Windows 7:
- Click Start>Computer.
- In the Search Computer input box, type the name of the file detected earlier, and press Enter.
- Once located, select the file then press SHIFT+DELETE to delete it.
- Repeat steps 2-4 for the remaining files.
*Note: Read the following Microsoft page if these steps do not work on Windows 7.
Step 6
Delete this registry key
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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\SystemCertificates\CA\Certificates
- 5A82739996ED9EBA18F1BBCDCCA62D2C1D670C
To delete the registry key this malware/grayware created:
- Open Registry Editor. Click Start>Run, type REGEDIT, then press Enter.
- In the left panel, double-click the following:
HKEY_CURRENT_USER>Software>Microsoft>SystemCertificates>CA>Certificates - Still in the left panel, locate and delete the key:
5A82739996ED9EBA18F1BBCDCCA62D2C1D670C - Close Registry Editor.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_BLYPT.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.
