Threat Descriptons



Category :


Type :


Aliases :

Sysbug, Andey, TrojanSpy.Win32.Andey, Backdoor.Sysbug, Troj/Sysbug-A, TrojanSpy.Win32.Sysbug


Sysbug is spying trojan with backdoor capabilities that was spread on 25th of November 2003. It was sent in email messages to a lot of email addresses. When activated, the trojan steals certain information from an infected computer. It can also download and activate executable files on an infected computer.


Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

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 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.

Technical Details

Sysbug trojan was spread in private-looking emails that looked like that:



Re[2]: Mary


Hello my dear Mary,
I have been thinking about you all night. I would like to
apologize for the other night when we made beautiful love and did
not use condoms. I know this was a mistake and I beg you to
forgive me.
I miss you more than anything, please call me Mary, I need you.
Do you remember when we were having wild sex in my house? I
remember it all like it was only yesterday. You said that the
pictures would not come out good, but you were very wrong, they
are great. I didn't want to show you the pictures at first, but
now I think it's time for you to see them. Please look in the
attachment and you will see what I mean.
I love you with all my heart, James.


The '' attachment contains the trojan's executable file with 'wendynaked.jpg.exe' name. The trojan's file is packed with UPX file compressor and is 11808 bytes long.

When run by a user, the trojan installs itself to system. It copies itself to Windows folder as 'sysdeb32.exe' file and creates a startup key for itself in the Registry:

"SystemDebug" = "%windir%\sysdeb32.exe"

where %windir% is the name of Windows directory. That way the trojan is started every time when Windows starts.

Being active, the trojan collects certain information from an infected computer and uploads this info to '' website via HTTP protocol. The trojan steals the following information:

POP server name, user name and password
NNTP server name and user name
SMTP server name, account name, display name, email address and organization name
RAS information
Edialer information

Beside the above mentioned data the trojan reports the following info to '' website:

IP address
unique ID
connection speed
active time

The trojan creates TEMP35.TXT file in the root folder of C: drive and SVC.SAV file in Windows folder. These are data files used by the trojan.

When active, the backdoor part of the trojan listens to TCP port 5555.

The trojan has the ability to download executable files and run them. The downloaded file is saved to 'c:\tmp.exe' file, which is then activated.

The trojan periodically connects to website. If it becomes widespread, it might cause a DoS (Denial of Service) attack on that server.

The trojan has a fake copyright message in its body:

/* Written By Adrey Karimov [] */
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