BKDR_SIMDA.UHU
TrojanDownloader:Win32/Cutwail.BF (Microsoft)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
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 connects to a website to send and receive information.
It deletes the initially executed copy of itself.
TECHNICAL DETAILS
132,096 bytes
EXE
Yes
16 Oct 2014
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:
- %System%\{random filename}.exe
- %User Profile%\{random filename}.exe
(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Profile% is a user's profile folder, where it usually is C:\Documents and Settings\{user name} on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name} on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It adds the following processes:
- svchost.exe
It injects codes into the following process(es):
- svchost.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
{random filename} = "%System%\{random filename}.exe"
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download a file
- Execute a file
- Execute CMD
- Inject file to a running process
It connects to the following websites to send and receive information:
- {BLOCKED}1.{BLOCKED}6.212.179:443
- {BLOCKED}5.{BLOCKED}1.161.13:443
- {BLOCKED}3.{BLOCKED}9.86.151:443
- {BLOCKED}5.{BLOCKED}5.208.192:443
- {BLOCKED}1.{BLOCKED}7.198.93:443
- {BLOCKED}6.{BLOCKED}1.200.70:443
- {BLOCKED}3.{BLOCKED}9.68.82:443
Information Theft
This backdoor gathers the following data:
- Processor information
- Country
- OS Version
Other Details
This backdoor deletes the initially executed copy of itself
SOLUTION
9.700
11.214.05
15 Oct 2014
11.215.00
15 Oct 2014
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_SIMDA.UHU
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
- {random filename} = "%System%\{random filename}.exe"
- {random filename} = "%System%\{random filename}.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_SIMDA.UHU. 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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