Risk: Medium
Security groups have been alerted to a buffer overflow vulnerability in a core operating system component, ntdll.dll. When exploited, the vulnerability allows attackers to execute arbitrary code, and escalate system privileges.
Microsoft released security bulletin MS03-007 in March, alerting customers of the issue for Windows 2000 systems running IIS5. Further investigation showed that the Windows NT4 version of ntdll.dll was also vulnerable. Microsoft have now confirmed that the XP version of ntdll.dll is also susceptible to attacks via any program that relies on the flawed system component.
Microsoft have updated their MS03-007 advisory to reflect this, and a patch is available.