Microsoft ASN flaw may be biggest defect ever found
Shawna McAlearney Feb 10 2004

Enterprises are scrambling to patch their systems in the wake of
Microsoft Corp.'s vulnerability blitz Tuesday that revealed a critical
flaw affecting multiple Windows operating systems. The vulnerability
can permit an unauthenticated, remote attacker to execute arbitrary
code with system privileges.


"It's the biggest Microsoft flaw we've found -- maybe the biggest ever
found," said Marc Maiffret, chief hacking officer at Aliso Viejo,
Calif.-based eEye Digital Security, which discovered the flaw.

"Because it's in a shared component, it has multiple avenues for
attacks -- everything from file sharing to IPSec."

According to Maiffret, the ASN.1 flaw was reported to Microsoft 200
days before the patch was released.

".. This was an instance in which due diligence required us to very
carefully evaluate the broadest possible implications of a single
anomaly reported to us." [Microsoft spokesperson]

In this instance, integer overflows and other flaws in integer
arithmetic cause a vulnerability in the ASN.1 parser library in
Microsoft Windows NT 4.0, 4.0 TSE, 2000, XP and Server 2003. According
to the Computer Emergency Response Team (CERT), any application that
loads the ASN.1 library could serve as an attack vector.,00.html