Feeds

NTLM authentication: still broken after all these years

Popular tech imperils users

Beginner's guide to SSL certificates

A 15-year-old vulnerability in technology used to authenticate users on Windows and Unix networks continues to put the organizations that rely on it at risk, a security researcher said on Thursday.

Short for NT LAN Manager, NTLM and its offspring, NTLMv2, is a challenge-and-response protocol for logging onto Microsoft accounts over Windows or Unix networks. While it encrypts credentials to prevent them from being captured, it still leaves much to be desired from a security perspective, says Marsh Ray, a researcher who was scheduled to speak about the weakness on Thursday at the Usenix Security Symposium in Washington, DC.

“The deeper problem is that NTLMv1-2 provide absolutely no protection against credentials forwarding/relay or reflection attacks,” Ray, who is a software developer at two-factor authentication service PhoneFactor, wrote in an email sent to journalists. “This means that an active attacker (such as a man-in-the-middle) is sometimes able to redirect the login of the legitimate user to authenticate his own session.

“For example, Alice connect to insecure public wifi -> Mallory gets into corporate Outlook Web Access or SSL VPN portal. It's that bad.”

Awareness of the protocol vulnerability dates back to 1996 and it has been the topic of several presentations over the years at various Black Hat security conferences, Ray says. Since that time, a variety of vendors have issued patches for the weakness. Microsoft alone has issued at least six related updates starting in 1999, including one in 2008 that was seven years in the making.

But a raft of software packages, including WebKit, Samba, and Mozilla titles, continue to be plagued by the problems, in large part because fixes tend to limit themselves to specific attack vectors at the expense of comprehensiveness. And that means that the flaw is likely of benefit to black-hat hackers.

“So after a little research and talking to quite a few people, my impression is the only people who really understand the scope and severity of this problem are some bad guys, some pen testers and a few people at MS and other vendors,” Ray warns. Referring to the software framework written for pen testers, he adds: “The Metasploit crew doesn't have the time and energy to write the finicky custom exploit code for every vulnerable configuration, but I would not make such an assumption about other teams of professionals.”

Extended excerpts of Ray's letter are published here. ®

Intelligent flash storage arrays

More from The Register

next story
You really need to do some tech support for Aunty Agnes
Free anti-virus software, expires, stops updating and p0wns the world
Regin: The super-spyware the security industry has been silent about
NSA fingered as likely source of complex malware family
You stupid BRICK! PCs running Avast AV can't handle Windows fixes
Fix issued, fingers pointed, forums in flames
Privacy bods offer GOV SPY VICTIMS a FREE SPYWARE SNIFFER
Looks for gov malware that evades most antivirus
Patch NOW! Microsoft slings emergency bug fix at Windows admins
Vulnerability promotes lusers to domain overlords ... oops
HACKERS can DELETE SURVEILLANCE DVRS remotely – report
Hikvision devices wide open to hacking, claim securobods
prev story

Whitepapers

Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Designing and building an open ITOA architecture
Learn about a new IT data taxonomy defined by the four data sources of IT visibility: wire, machine, agent, and synthetic data sets.
How to determine if cloud backup is right for your servers
Two key factors, technical feasibility and TCO economics, that backup and IT operations managers should consider when assessing cloud backup.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.