Feeds

LSD puts Sendmail bug under the microscope

Proof of concept

  • alert
  • submit to reddit

Choosing a cloud hosting partner with confidence

Polish ethical hackers Last Stage of Delirium (LSD) yesterday published proof of concept code for a serious flaw in Sendmail which emerged this week.

In a posting to BugTraq yesterday, LSD provides a detailed analysis of the buffer overflow vulnerability for the first time.

Previous advisories on the flaw, which has been present in Sendmail (undiscovered) for some years, are noticeably lacking in detail.

The vulnerability resides within the crackaddr(char* addr) function of the headers.c file, according to LSD's research. Ironically this function is designed to be a security mechanism.

Based on their preliminary work the Poles tentatively suggest the Sendmail vulnerability is less bad than
it first appeared.

"Due to the nature of the discussed Sendmail vulnerability it seems that it is unexploitable on most of commercially available UNIX systems," LSD writes. "It also doesn't seem to be exploitable on most of the default SMTP installations of x86 based open-source systems.

"This leads to the conclusion that the overall impact of the vulnerability is rather limited and not so significant as it might be thought," the group adds.

By its own admission, LSD's analysis is not exhaustive, testing only for one possible exploit mechanism on Unix and (Slackwave and Red Hat) Linux servers. So don't read too much into the group's conclusions just yet.

"We cannot exclude that there does not exist another execution path in the Sendmail code, that could lead to the program counter overwrite," LSD writes.

In a follow-up post, Sendmail's Eric Allman points out patches still need to be applied.

"Please don't breath a sigh of relief because you are running on one of the 'does not crash' systems," he writes.

"Besides direct execution path exploits, there are other variables that are not pointers that have security implications; finding one of them within range will be more difficult, but probably not impossible." ®

Related Stories

Sendmail vuln. Patch now
Slammer: Why security benefits from proof of concept code
Open and closed security are roughly equivalent
FBI names 20 most unwanted security flaws

External Links

CERT advisory: Remote Buffer Overflow in Sendmail
Patch application and testing tool from Sendmail

Beginner's guide to SSL certificates

More from The Register

next story
FYI: OS X Yosemite's Spotlight tells Apple EVERYTHING you're looking for
It's on by default – didn't you read the small print?
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Edward who? GCHQ boss dodges Snowden topic during last speech
UK spies would rather 'walk' than do 'mass surveillance'
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
'LulzSec leader Aush0k' found to be naughty boy not worthy of jail
15 months home detention leaves egg on feds' faces as they grab for more power
China is ALREADY spying on Apple iCloud users, claims watchdog
Attack harvests users' info at iPhone 6 launch
Carders punch holes through Staples
Investigation launched into East Coast stores
prev story

Whitepapers

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.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
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.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.