Sober.H, I-Worm.Sober.h


Sober.H appeared on June 11th, 2004. This Sober variant doesn't spread itself in emails. Instead, it mass-mails political statements. It might have been downloaded to computers already infected by earlier Sober variant, Sober.G for example.

Automatic action

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Suspect a file is incorrectly detected (a False Positive)?

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest detection database updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    NOTE If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note You need administrative rights to change the settings.

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Technical Details

Sober.H is written in Visual Basic. Its file is a PE executable 59747 bytes long, packed with UPX file compressor. Sober.H has its own SMTP engine.

Installation to system

Sober.H's file is started installs itself to system. It copies itself to Windows System folder with a semi-randomly generated name and EXE extension. The following text strings are used to generate the file name of the Sober's executable:


After that Sober.H creates startup keys for its file in Windows Registry. The key names are also semi-randomly generated from the above given list. The following keys are created:

[HKCU\Software\Microsoft\Windows\CurrentVersion\Run]  "" = "%WinSysDir%\.exe"  [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]  "" = "%WinSysDir%\.exe"   

During its installation cycle Sober.H creates the following files in Windows System folder:

"" = "%WinSysDir%\.exe"
"" = "%WinSysDir%\.exe"

These files have zero length and they are used to disable previous variants of Sober if they are installed on an infected computer.

Sending emails

Sober.H sends different email messages with political statements. It doesn't attach itself to these messages.

Before spamming Sober.H scans files with certain extensions on all hard disks to harvest email addresses. Files with the following extensions are scanned:

"" = "%WinSysDir%\.exe"
"" = "%WinSysDir%\.exe"

The found email addresses and user names are saved in these 2 files that Sober.H creates in Windows System folder:

"" = "%WinSysDir%\.exe"
"" = "%WinSysDir%\.exe"

When Sober.H is active in memory it blocks access to these files as well as to its executable file.

Sober.H ignores email addresses that contain any of the following substrings:

"" = "%WinSysDir%\.exe"
"" = "%WinSysDir%\.exe"


Sober.H can download and activate an executable file from the following website:

"" = "%WinSysDir%\.exe"
"" = "%WinSysDir%\.exe"

The name of the downloaded executable file is 'winhlpx32ll.exe'.

Deactivation of Sober.H

Sober.H periodically looks for a file named 'sysmms32.lla' and it this file is found, it uninstalls itself from memory. Moreover, if this file is present in Windows System folder, Sober.H does not install itself to a system.