Exactly a week after Microsoft announced a
SSL vulnerability affecting key Windows products, malicious hackers
unveiled exploits that could lead to widespread
denial-of-service attacks
The exploit code, described in the underground as the “SSL Bomb,” could
allow specially crafted SSL packets to force the Windows 2000 and Windows XP
operating systems to block SSL connections. On Windows Server 2003
machines, the code could cause the system to reboot, security experts
warned.
The code targets a vulnerability outlined last Tuesday when the software
giant released
a flurry of “critical” patches to plug security holes.
According to an advisory from the
SANS institute, the threat level could grow considerably if malicious
attackers take control of unpatched servers and systems.
Microsoft has
already issued a patch in its MS04
-001 advisory but the SANS institute believes it’s only a matter of time
before exploits with remote code execution appear in the wild.
SANS also warned of a variant of the Gaobot.XZ worm which has been
actively scanning ports to try to explore an old vulnerability of the UPnP
service, described in Microsoft Security Bulletin MS01-059.
“Judging by the
recent variants, looks like the virus writers are trying, more than usual, to
get unpatched machines, both exploring services and applications,” the
institute said in an alert.
The W32.Gaobot.ZX worm, first detected April 12, attempts to spread through networks with weak
passwords, and allows attackers to access an infected computer using
a predetermined IRC channel.
The worm targets multiple vulnerabilities to spread, including the DCOM
RPC vulnerability (described in Microsoft Security Bulletin MS03-026); the
WebDav vulnerability (described in Microsoft Security Bulletin MS03-007);
and the Workstation service buffer overrun vulnerability (described in
Microsoft Security Bulletin MS03-049).
