Re: Blaster Variant - W32.Blaster.B.Worm

From: Joe Stewart (jstewartat_private)
Date: Thu Aug 14 2003 - 12:18:08 PDT

  • Next message: David Gillett: "RE: msblast.exe worm FINDINGS (DDoS) ---> Can someone please confirm?"

    On Thursday 14 August 2003 07:29 am, Bruce Martins wrote:
    > It would seem that there is a third according to Symantec
    >
    > http://securityresponse.symantec.com/avcenter/venc/data/w32.blaster.c.wo
    > rm.html
    >
    > Which drops in a little backdoor component has anyone seen this one out
    > there yet?
    
    The Blaster.c "variant" worm doesn't drop the backdoor component - the
    index.exe dropper drops the worm AND the backdoor. The Blaster.c worm 
    itself is nothing more than Blaster.a with some string data altered, the
    filename changed and repacked with FSG instead of UPX. The worm then 
    carries out the same functions as Blaster.a. It does not spread the backdoor
    around, so you may see systems infected with the Blaster.c worm but not the
    backdoor (if it manages to spread at all in the wake of Blaster.a). The
    dropper package  is probably being spread manually or via an auto-rooter,
    since it has no integrated code to copy itself to infected systems.
    
    The Blaster.b (p 3 n 1 s) variant is nothing more than the Blaster.a variant
    with one string changed, the file renamed and repacked with upx.
    
    -Joe
    
    -- 
    Joe Stewart, GCIH 
    Senior Security Researcher
    LURHQ Corporation
    http://www.lurhq.com/
    
    
    ---------------------------------------------------------------------------
    Captus Networks - Integrated Intrusion Prevention and Traffic Shaping  
     - Instantly Stop DoS/DDoS Attacks, Worms & Port Scans
     - Automatically Control P2P, IM and Spam Traffic
     - Ensure Reliable Performance of Mission Critical Applications
     - Precisely Define and Implement Network Security and Performance Policies
    **FREE Vulnerability Assessment Toolkit - WhitePapers - Live Demo
    Visit us at: 
    http://www.securityfocus.com/sponsor/CaptusNetworks_incidents_030814
    ----------------------------------------------------------------------------
    



    This archive was generated by hypermail 2b30 : Thu Aug 14 2003 - 17:03:31 PDT