TROJ_UPATRE.YYRK
Downloader.Upatre (Symantec); Trojan.Win32.Staser.atfe (Kaspersky)
Windows
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
Downloaded from the Internet
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.
It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
It deletes itself after execution.
TECHNICAL DETAILS
27,648 bytes
EXE
No
10 Jan 2015
Connects to URLs/IPs, Downloads files
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:
- %User Temp%\uaygf.exe
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)
Other System Modifications
This Trojan adds the following registry keys:
HKLM\Software\Microsoft\
ESENT\Process\document81723\
DEBUG
Trace Level = null
Download Routine
This Trojan accesses the following websites to download files:
- http://{BLOCKED}ersalliance.org/wp-includes/images/guid11.pdf
- http://{BLOCKED}ksupport.net/docs/guid11.pdf
It saves the files it downloads using the following names:
- %Windows%\bOgFvXkJnpTpwX.exe
(Note: %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.)
It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.
Other Details
This Trojan deletes itself after execution.
NOTES:
This Trojan accesses the URL {BLOCKED}.{BLOCKED}.35.133:33136/0912us21/{Computer Name}/0/{OS Version}-{Service Pack}/0/ to send information. The following information are posted:
- Computer name
- Operating system version
- Service pack installed
SOLUTION
9.700
11.354.07
18 Dec 2014
11.355.00
19 Dec 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
Search and delete these files
- %User Temp%\uaygf.exe
- %Windows%\bOgFvXkJnpTpwX.exe
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_LOCAL_MACHINE\Software\Microsoft\ESENT\Process\document81723\DEBUG
- Trace Level = null
- Trace Level = null
Step 5
Scan your computer with your Trend Micro product to delete files detected as TROJ_UPATRE.YYRK. 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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