Ebury and Mayhem server malware families still active

Posted by   Martijn Grooten on   Oct 31, 2017

Whether it is to send spam or to redirect web traffic to malicious payloads, compromised (Linux) web servers are the glue in many a malware campaign. Two such networks of compromised servers – about which VB has published papers in the past – have recently received updates.

The paper 'Operation Windigo' (pdf) was published by ESET in 2014 and looked at a cybercrime operation that used various Linux malware families, including the Ebury OpenSSH backdoor, which was used to access servers and steal credentials, and the Cdorked HTTP backdoor, which was used for web traffic redirection.

At VB2014, researchers from ESET in Canada and Yandex in Russia shared the stage to present a paper on these malware families, and at the same event, the authors of the Operation Windigo paper were the winners of the first Péter Szőr award.

The work the ESET researchers did on this group wasn't merely technical though: they also assisted the FBI in an international operation against the conspirators behind the malware, which led to the arrest of one individual at the Finnish-Russian border in August 2015. The suspect was subsequently extradited to the United States where he pleaded guilty and was sentenced to 46 months in prison.

Despite this setback, the group is still active. Yesterday, ESET published a blog post highlighting various updates to the Ebury malware, which include self-hiding techniques and a domain generating algorithm (DGA) that signs DNS TXT records to mitigate possible attempts to sinkhole the botnet.

penguins_wikimedia_commons.jpg

Various generations of penguins. Source: Wikimedia commons.

Also in 2014, Virus Bulletin published a paper by the same group of Yandex researchers, on the Mayhem botnet they had discovered. What made this botnet of Linux servers particularly noteworthy was the fact that it operated under restricted privileges and thus didn't require root access on the infected machines. The clear separation of root and user accounts on Linux is often cited as a strong built-in defence against malware.

A blog post by Sucuri shows that the Mayhem botnet is still active and has updated itself, removing any traces of the MAYHEM_DEBUG server variable, while masquerading as a jquery library.

A combination of operating system hardening and security software for added protection has made both desktop and mobile operating systems more secure than ever. This has made Linux servers a relatively easy and rather attractive target for malware authors. It is thus unlikely that we have seen the end of such attacks.

twitter.png
fb.png
linkedin.png
hackernews.png
reddit.png

 

Latest posts:

VB2021 call for papers - now open, to all!

The call for papers for VB2021 is now open and we want to hear from you - we're planning for flexible presentation formats, so everyone is encouraged to submit, regardless of whether or not you know at this stage whether you'll be able to travel to…

In memoriam: Yonathan Klijnsma

We were very sorry to learn of the passing of researcher Yonathan Klijnsma last week. Here, former VB Editor Martijn Grooten shares his memories of a talented researcher and a very kind person: this month, infosec lost a really good one.

VB2020 localhost videos available on YouTube

VB has made all VB2020 localhost presentations available on the VB YouTube channel, so you can now watch - and share - any part of the conference freely and without registration.

VB2020 presentation & paper: 2030: backcasting the potential rise and fall of cyber threat intelligence

At VB2020 localhost, threat intelligence consultant Jamie Collier used the analytical technique of backcasting to look at the rise and fall of the cyber threat intelligence industry.

VB2020 presentation: Behind the Black Mirror: simulating attacks with mock C2 servers

At VB2020 localhost, Carbon Black's Scott Knight presented an approach he and his colleagues have taken to more realistically simulate malware attacks.

We have placed cookies on your device in order to improve the functionality of this site, as outlined in our cookies policy. However, you may delete and block all cookies from this site and your use of the site will be unaffected. By continuing to browse this site, you are agreeing to Virus Bulletin's use of data as outlined in our privacy policy.