[ISN] Sobig linked to DDoS attacks on anti-spam sites

From: InfoSec News (isn@private)
Date: Fri Sep 26 2003 - 01:25:11 PDT

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    By John Leyden
    Posted: 25/09/2003 
    A senior anti-spam activist is calling on law enforcement authorities
    to track down the perpetrators behind a widespread and sustained
    attack on anti-spam sites. The call, from Steve Linford of Spamhaus,
    comes along with fresh evidence that the assaults have been enabled by
    the infamous Sobig worm.
    Earlier this week two anti-spam services, Monkeys.com and the
    Compu.Net "block list", announced their closure due to DDoS attacks,
    and other attempts by spammers to make their operation as difficult as
    possible. Their closure follows an earlier decision to discontinue the
    popular if controversial SPEWS block list (which was run by
    Osirusoft.com) for similar reasons (see postings to
    news.admin.net-abuse.email for more info).
    Linford tells The Reg that Spamhaus has been under constant "extremely
    heavy" DDoS attack since early July. He believes the attack against
    his site and others originates from Windows machines infected with the
    Sobig worm, controlled by spammers over IRC networks.
    The Sobig worm is known to install Trojan code on infected PCs turning
    them into "zombies" capable of relaying spam messages or attacking
    other machines.
    "Sobig has created a network of tens of thousands of zombie machines
    that have left a DDoS arsenal in the hands of spammers," Linford said.
    Linford's theory is backed up by a recent study by managed services
    firm MessageLabs which shows a strong correlation between the origin
    of spam messages and the IP addresses of Windows machines infected by
    the Sobig, Fizzer or BugBear viruses. Matt Sergeant, senior anti-spam
    technologist at MessageLabs, said 70 per cent of the spam the company
    blocked came from open proxies. Half of these open proxies were
    established via Trojan infection with the rest being due to mistakes
    in setting up machines, he estimates.
    According to Sergeant, a DDoS attack against anti-spam sites fits the
    profile of malevolent use for a Sobig-infected network of zombie
    clients. However, he adds, he has "no hard evidence" to prove this one
    way or the other.
    Spamhaus Linford makes no such equivocations. He, like others, is
    convinced that Sobig was commissioned by spammers and is now been used
    as part of a sinister plan to force end users to spend more time
    wading through useless junk mail.
    "Spammers have thrown this network of spam zombies against whatever
    stands in their path," he said.
    Linford said Spamhaus has a large distributed network which has thus
    far been able to "absorb attacks", unlike smaller operations that have
    been "picked off one by one".
    Thankfully other anti-spam organisations have picked up the roles of
    the spam fighters forced to close in recent weeks.
    Because of this the attacks have failed to have a substantial effect
    of the absolute quantities of spam going through. But they have had an
    effect on the morale of anti-spam fighters, Linford concedes.
    Linford is calling on law enforcements authorities to investigate who
    is controlling machines infected by the Sobig virus. Surveillance on
    IRC server channels can be used to identify the "zombie master" behind
    the criminal DDoS attacks of anti-spam organisations.
    But only police have the ability and legal powers to carry out such
    tracking and surveillance operations, Linford argues.
    "Government makes extensive use of anti-spam services and this network
    of zombie machines could easily be turned against government. The
    authorities need to find the people behind these attacks for their own
    interests, if for no other reason," Linford added.
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