[ISN] Unscheduled Windows update kills critical security bug under active attack

http://arstechnica.com/security/2014/11/unscheduled-windows-update-kills-critical-security-bug-under-active-attack/ By Dan Goodin Ars Technica Nov 18 2014 Microsoft has released an unscheduled update to patch a critical security hole that is being actively exploited to hack Windows-based servers. A flaw in the Windows implementation of the Kerberos authentication protocol allows attackers with credentials for low-level accounts to remotely hijack extremely sensitive Windows domain controllers that allocate privileges on large corporate or government networks. The privilege elevation bug is already being exploited in highly targeted attacks and gives hackers extraordinary control over vulnerable networks. “The only way a domain compromise can be remediated with a high level of certainty is a complete rebuild of the domain,” Microsoft engineer Joe Bialek wrote in a blog post accompanying Thursday’s patch. “An attacker with administrative privilege on a domain controller can make a nearly unbounded number of changes to the system that can allow the attacker to persist their access long after the update has been installed. Therefore it is critical to install the update immediately.” The patch came on the same day that security research firm NSS Labs reported recently discovering reliable attacks in the wild that exploit security holes patched by MS14-064, an update released last week. The exploits use proof-of-concept code also released last week to install unspecified malware on vulnerable computers, NSS said. […]