BKDR_ZEGOST.YN
Backdoor:Win32/Zegost.BZ(Microsoft), BDS/Zegost.BZ.226(AntiVir), Virus.Win32.Dialer(Ikarus)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
Threat Type: Backdoor
Destructiveness: No
Encrypted:
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 deletes registry entries, causing some applications and programs to not function properly.
TECHNICAL DETAILS
168,061 bytes
EXE
Yes
26 Jun 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.
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
x7 = "{malware path and file name}"
Other System Modifications
This backdoor adds the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Hardware Profiles\Current\System\
CurrentControlSet\Enum\PCI\
VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\{value}
CSConfigFlags = "0"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\PCI\VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\
{value}\Control
DisableCount = "0"
It deletes the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Enum\PCI\VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\
{value}\LogConf
BootConfig = {hex values}
Other Details
This backdoor connects to the following possibly malicious URL:
- {BLOCKED}2014.f3322.org
SOLUTION
9.700
10.886.04
26 Jun 2014
10.887.00
26 Jun 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
Restart in Safe Mode
Step 3
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
- x7 = "{malware path and file name}"
- x7 = "{malware path and file name}"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Hardware Profiles\Current\System\CurrentControlSet\Enum\PCI\VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\{value}
- CSConfigFlags = "0"
- CSConfigFlags = "0"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\PCI\VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\{value}\Control
- DisableCount = "0"
- DisableCount = "0"
Step 4
Restore this deleted registry key/value from backup
*Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\PCI\VEN_{value1}&DEV_{value2}&SUBSYS_{value3}&REV_{value4}\{value}\LogConfBootConfig = {hex values}
Step 5
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_ZEGOST.YN. 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.
Step 6
Scan your computer with your Trend Micro product to delete files detected as BKDR_ZEGOST.YN. 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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