RANSOM_BRLOCK.A
a variant of MSIL/LockScreen.PG trojan (ESET)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted: Yes
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.
TECHNICAL DETAILS
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.
Installation
This Trojan drops the following copies of itself into the affected system and executes them:
- %ProgramData%\JavaTM\LaunchTM.exe
(Note: %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
LaunchTM = "%ProgramData%\JavaTM\LaunchTM.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
Userinit = "userinit.exe, %ProgramData%\JavaTM\LaunchTM.exe"
Other Details
This Trojan does the following:
- It restarts the system by executing the following command:
- shutdown.exe -r -t 0
- It locks the screen and displays the ransom note by loading the following site:
- http://{BLOCKED}niypomidor.ru/system/engine/inc/?download={OS Version}
However, as of this writing, the site is inaccessible.
- It checks if any of the following strings are present in the running processes:
- autoruns.
- avenger
- confick
- filemon
- gmer
- klwk
- vmtoolsd.
- procexp
- procmon
- regmon
- scct_
- sysclean
- tcpview
- wireshark
- avz.
- regcool
- tcpview
- rtsniff
- packetcapture
- peepnet
- capturenet
- aps.
- nepenthes
- sandbox
- VMwareUser.
- ollydbg
- fiddler
- syser
- ida.
- immunity
- httpdebugger
- cff explorer
If found, it sleeps for 12 days
- bcdedit /set {current} bootems off
- bcdedit /set {current} advancedoptions off
- bcdedit /set {current} optionsedit off
- bcdedit /set {current} bootstatuspolicy IgnoreAllFailures
- bcdedit /set {current} recoveryenabled off
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot
AlternateShell = "cmd.exe_"
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
Identify and delete files detected as RANSOM_BRLOCK.A using either the Startup Disk or Recovery Console
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
- LaunchTM = "%ProgramData%\JavaTM\LaunchTM.exe"
- LaunchTM = "%ProgramData%\JavaTM\LaunchTM.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- Userinit = "userinit.exe, %ProgramData%\JavaTM\LaunchTM.exe"
- Userinit = "userinit.exe, %ProgramData%\JavaTM\LaunchTM.exe"
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as RANSOM_BRLOCK.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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