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TrojanDownloader:Win32/Umbald.A


TrojanDownloader:Win32/Umbald.A is a trojan that silently downloads and installs other programs without consent. This could include the installation of additional malware or malware components to an affected computer.


What to do now

To detect and remove this threat and other malicious software that may have been installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following: For more information about using antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.

Threat behavior

TrojanDownloader:Win32/Umbald.A is a trojan that silently downloads and installs other programs without consent. This could include the installation of additional malware or malware components to an affected computer.
Installation
When executed, TrojanDownloader:Win32/Umbald.A copies itself to %windir%\winsvchost.exe.

The malware modifies the following registry entries to ensure that its copy executes at each Windows start:

Adds value: "Windows Updater"
With data: "c:\windows\winsvchost.exe"
To subkey: HKCU\Software\Microsoft\windows\currentversion\run
Payload
Contacts remote host
TrojanDownloader:Win32/Umbald.A may contact a remote host at a1.livefeed916.com using port 80. Commonly, malware may contact a remote host for the following purposes:
  • To report a new infection to its author
  • To receive configuration or other data
  • To download and execute arbitrary files (including updates or additional malware)
  • To receive instruction from a remote attacker
  • To upload data taken from the affected computer

This malware description was produced and published using our automated analysis system's examination of file SHA1 a02f894bd03fecad453fb333e921570bbf57972b.

Symptoms

System changes
The following system changes may indicate the presence of this malware:

  • The presence of the following files:

  • %windir%\winsvchost.exe

  • The presence of the following registry modifications:
  • Adds value: "Windows Updater"
    With data: "c:\windows\winsvchost.exe"
    To subkey: HKCU\Software\Microsoft\Windows\CurrentVersion\Run


Prevention


Alert level: Severe
First detected by definition: 1.113.1508.0
Latest detected by definition: 1.183.2451.0 and higher
First detected on: Oct 12, 2011
This entry was first published on: Oct 20, 2011
This entry was updated on: Oct 26, 2011

This threat is also detected as:
  • Trojan-Downloader.Win32.Agent.szfc (Kaspersky)