Menu
'Ghost' vulnerability poses high risk to Linux distributions

'Ghost' vulnerability poses high risk to Linux distributions

The flaw in the GNU C Library can be exploited remotely for full control, according to Qualys

A fault in a widely used component of most Linux distributions could allow an attacker to take remote control of a system after merely sending a malicious email.

The vulnerability, nicknamed "Ghost," is in the GNU C Library known as glibc, according to security vendor Qualys, which disclosed the issue on Tuesday as many Linux distributions released patches. Glibc is a C library that defines system calls.

Red Hat, Debian, Ubuntu and Novell have issued fixes. It is advised administrators should patch as soon as possible.

The bug first appeared in glibc in 2000. It actually was fixed on May 21, 2013, in between versions 2.17 and 2.18, Qualys CTO Wolfgang Kandek wrote in a blog post.

But at the time, the flaw wasn't recognized as a security risk, Kandek wrote. Most stable and long-term support Linux distributions weren't immediately modified, including Debian 7, Red Hat Enterprise Linux 6 and 7, CentOS 6 and 7 and Ubuntu 12.04.

Qualys found the problem during a code audit. It's unclear whether attackers exploited the vulnerability before it was found by the company.

It is one of many issues found over the last year in open-source software components, including Heartbleed, Poodle and Shellshock, that have caused alarm due to the large number of systems affected.

The flaw in Glibc exposes a buffer overflow that can be triggered locally and remotely in the "gethostbyname" functions. Applications using glibc get access to a DNS resolver, which converts hostnames into an IP address, Kandek wrote.

Qualys analysts developed a proof-of-concept exploit where they sent a specially crafted email to an Exim mail server running the vulnerable version of glibc and achieved a remote shell, giving them full control.

The company is not releasing the exploit until about half of all affected machines are patched, Kandek wrote. In a detailed advisory, Qualys said it will eventually release a Metasploit module for it. Metasploit is a toolkit used for penetration testing.

The issue with glibc could be "an annoying one to fix," wrote Mattias Geniar, a systems engineer with the Belgian hosting provider Nucleus, in a blog post.

"The update is in the glibc package, but that's a set of libraries that are being used by a lot of running services," Geniar wrote. "After the update, each of these services needs to be restarted."

He wrote the best action would be to reboot an entire server after it has been updated, and at minimum restart all public-facing services such as Web servers and mail servers.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Follow Us

Join the New Zealand Reseller News newsletter!

Error: Please check your email address.

Tags securityExploits / vulnerabilitiesqualys

Slideshows

Top 50 defining moments of the New Zealand channel in 2016

Top 50 defining moments of the New Zealand channel in 2016

Reseller News looks back on a tumultuous 12 months for the New Zealand channel, assessing the fallout from a year of sizeable industry change. Whether it be local or global mergers and acquisitions, distribution deals or job changes, the channel that started the year differs somewhat to the one set to finish it - Reseller News assesses the key moments that made 2016.​

Top 50 defining moments of the New Zealand channel in 2016
​Hewlett Packard Enterprise honours high achieving NZ channel

​Hewlett Packard Enterprise honours high achieving NZ channel

Hewlett Packard Enterprise honoured its top performing Kiwi partners at the second running of its HPE Partner Awards in New Zealand, held at a glitzy ceremony in Auckland. Recognising excellence across eight categories - from distributors to resellers - the tech giant celebrated its first year as a standalone company, following its official split from HP in 2015.

​Hewlett Packard Enterprise honours high achieving NZ channel
Nutanix treats channel partners to Christmas cruise

Nutanix treats channel partners to Christmas cruise

Nutanix recently took to the seas for a Christmas Cruise around Sydney Harbour with its Australia and New Zealand staff, customers and partners to celebrate a stellar year for the vendor. With the sun out, they were all smiles and mingled over drinks and food.

Nutanix treats channel partners to Christmas cruise
Show Comments