TROJ_INJECTOR.YYRL
Trojan:Win32/Dynamer!ac (Microsoft); Trojan-Dropper.Win32.Dapato.epyg (Kaspersky)
Windows
Threat Type: Trojan
Destructiveness: No
Encrypted:
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
396,734 bytes
EXE
Yes
14 Oct 2014
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 files:
- %All Users Profile%\{random}\{random}.dat
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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 creates the following folders:
- %All Users Profile%\{random}
(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)
Autostart Technique
This Trojan creates the following registry entries to enable automatic execution of dropped component at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "regsvr32.exe "%All Users Profile%\{random}\{random}.dat""
Other System Modifications
This Trojan adds the following registry keys:
HKEY_CLASSES_ROOT\CLSID\{CLSID 1}
HKEY_CLASSES_ROOT\CLSID\{CLSID 2}
HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 1}
HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 2}
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
NoProtectedModeBanner = "1"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
TabProcGrowth = "0"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
2500 = "3"
HKEY_CLASSES_ROOT\CLSID\{CLSID 1}
#sd = {"hex value}
HKEY_CLASSES_ROOT\CLSID\{CLSID 1}
#cert = {"hex value}
HKEY_CLASSES_ROOT\CLSID\{CLSID 2}
{CLSID 3} = {"hex value}
HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 1}
#sd = {"hex value}
HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 1}
#cert = {"hex value}
HKEY_CURRENT_USER\Software\Classes\
CLSID\{CLSID 2}
{CLSID 3} = {"hex value}
SOLUTION
9.700
11.210.04
14 Oct 2014
11.213.00
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
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 key
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_CLASSES_ROOT\CLSID
- {CLSID 1}
- {CLSID 1}
- In HKEY_CLASSES_ROOT\CLSID
- {CLSID 2}
- {CLSID 2}
- In HKEY_CURRENT_USER\Software\Classes\CLSID
- {CLSID 1}
- {CLSID 1}
- In HKEY_CURRENT_USER\Software\Classes\CLSID
- {CLSID 2}
- {CLSID 2}
Step 5
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- {random} = "regsvr32.exe "%All Users Profile%\{random}\{random}.dat""
- {random} = "regsvr32.exe "%All Users Profile%\{random}\{random}.dat""
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- NoProtectedModeBanner = "1"
- NoProtectedModeBanner = "1"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
- TabProcGrowth = "0"
- TabProcGrowth = "0"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\3
- 2500 = "3"
- 2500 = "3"
Step 6
Search and delete these folders
- %All Users Profile%\{random}
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_INJECTOR.YYRL. 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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