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.
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
SonyAgent = "{Malware Path and File Name}"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Request spam email messages structure and template
- Send spam email messages
- Send stolen information
- Get operating system information
- Get drive information
- List running processes
- Download and execute arbitrary files
- Update server with a list of compromised computers
- Manage registry
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- http://{BLOCKED}.{BLOCKED}.165.213
- http://{BLOCKED}.{BLOCKED}.254.8
- http://{BLOCKED}.{BLOCKED}.171.3
- http://{BLOCKED}.{BLOCKED}.145.158
- http://{BLOCKED}.{BLOCKED}.82.85
- http://{BLOCKED}.{BLOCKED}.82.86
- http://{BLOCKED}.{BLOCKED}.192.204
Information Theft
This backdoor gathers the following data:
- Network traffic information
- Login credentials from FTP, POP3 and SMTP traffic
It attempts to steal stored account information used in the following installed File Transfer Protocol (FTP) clients or file manager software:
- 32 Bit FTP
- BitKinex
- Bullet Proof FTP
- BulletProof FTP Client
- BulletProof FTP Client 2009
- BulletProof FTP Client 2010
- Classic FTP
- Core FTP
- CuteFTP
- CuteFTP 6 Home
- CuteFTP 6 Professional
- CuteFTP 7 Home
- CuteFTP 7 Professional
- CuteFTP 8 Home
- CuteFTP 8 Professional
- CuteFTP Lite
- CuteFTP Pro
- Directory Opus
- FAR Manager FTP
- FFFTP
- FTP Commander
- FTP Commander Deluxe
- FTP Commander Pro
- FTP Control
- FTP Explorer
- FTP Navigator
- FTPRush
- Far
- Far2
- FileZilla
- FlashFXP
- Fling
- Fling FTP
- Frigate3 FTP
- GPSoftware
- GlobalSCAPE
- Ipswitch
- Leap FTP
- NetDrive
- SecureFX
- SmartFTP
- SoftX FTP Client
- Sota FFFTP
- Total Commander
- TurboFTP
- UltraFXP
- WebDrive
- WinSCP
NOTES:
This backdoor modifies its file attributes into Read-only and Hidden after execution.
It also installs WinPcap, a legitimate and commonly used Windows packet capture library, which is used to monitor the infected computer's network activities by dropping and installing the following files:
- %System%\packet.dll - non-malicious
- %System%\wpcap.dll - non-malicious
- %System%\drivers\npf.sys - non-malicious
It exchanges encrypted messages with a remote server via HTTP protocol (TCP port 80). It uses the following crafted User-Agent when communicating with the remote host:
- Mozilla/5.0 (Windows; U; Windows NT; rv:1.9.2.17) Gecko/20110420 Firefox/3.6.17
It sends spam email messages using Simple Mail Transfer Protocol (SMTP) connection. It harvests email addresses from the affected computer's local drive.
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 BKDR_KELIHOS.NAP
Step 3
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 4
Delete this registry value
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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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
- SonyAgent = "{Malware Path and File Name}"
To delete the registry value this malware created:
- Open Registry Editor. To do this, click Start>Run, type regedit in the text box provided, then press Enter.
- In the left panel of the Registry Editor window, double-click the following:
HKEY_LOCAL_MACHINE>SOFTWARE>Microsoft>Windows>CurrentVersion>Run - In the right panel, locate and delete the entry:
SonyAgent = "{Malware Path and File Name}" - Close Registry Editor.
Step 5
Search and delete these files
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There may be some 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.
- %System%\packet.dll
- %System%\wpcap.dll
- %System%\drivers\npf.sys
To delete malware/grayware files:
- Search for the following files:
- %System%\packet.dll
- %System%\wpcap.dll
- %System%\drivers\npf.sys
Note: To do a search for the following files, right-click Start then click Search... or Find..., depending on the version of Windows you are running. For each file to be deleted, type its file name in the Named input box. In the Look In drop-down list, select My Computer, then press Enter. - Once located, select the file then press SHIFT+DELETE to permanently delete the file.
- Repeat the said steps for all files listed.
Step 6
Search and delete the file detected as BKDR_KELIHOS.NAP
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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 files in the search result.
To manually delete a malware/grayware file from the affected system:
- 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.
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_KELIHOS.NAP. 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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