BKDR_SANDPI.A
Trojan:Win32/Dynamer!ac(Microsoft);W32/SANDPI.A!tr(Fortinet);Trojan/Win32.Backdoor(AhnLab-V3)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: No
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.
It executes commands from a remote malicious user, effectively compromising the affected system.
It steals certain information from the system and/or the user.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
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 drops the following copies of itself into the affected system and executes them:
- {FOLDER NAME}\dnsapi.exe
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
DNSAPI = ""{FOLDER NAME}\dnsapi.exe" -k"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Infostealing Routine
- Drop Files
- Read Files
- Delete Files
- Get Running Processes
- Terminate process
- Create New Process
- Traverse Folders
- Enumerate Folders
- Get Drive Information
- Rename Files
- Enumerate Files
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}2.{BLOCKED}1.183.9:443
- {BLOCKED}1.{BLOCKED}9.166.82:8000
- {BLOCKED}1.{BLOCKED}9.201.5:8000
- {BLOCKED}0.{BLOCKED}9.170.166:88
- {BLOCKED}1.{BLOCKED}9.166.82:88
- {BLOCKED}1.{BLOCKED}9.201.5:88
- {BLOCKED}6.{BLOCKED}6.178.174:8000
- {BLOCKED}9.6{BLOCKED}.145.131:8000
- {BLOCKED}6.{BLOCKED}1.78.46:443
Information Theft
This backdoor steals the following information:
- Computer name
- OS information
- OS product type
- Build no. of the system
- System information(processor type, no of processors, page size, architecture)
- Network information (adapters)
- Processor / Hardware info
Other Details
This backdoor deletes the initially executed copy of itself
NOTES:
The malware only drops a copy of itself and creates an autorun registry if the malware is executed on at least the second level directory (e.g.: C:\{Folder 1}\{Folder 2}\malware.exe).
It always drops its copy in the second level directory.
SOLUTION
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
Step 4
Delete this registry value
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
- DNSAPI = ""{FOLDER NAME}\dnsapi.exe" -k"
- DNSAPI = ""{FOLDER NAME}\dnsapi.exe" -k"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SANDPI.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.
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