41% of spam sent via Rustock botnet

Posted by   Virus Bulletin on   Aug 26, 2010

Botnet spam back after short summer break.

In its latest intelligence report, security firm MessageLabs reports that 41% of all spam is being sent through the Rustock botnet, an increase of 9% since April. The botnet sends an estimated 32 million spam emails per minute.

Interestingly, the number of bots controlled by Rustock's botherders has almost halved in the same period. One of the reasons for this apparent contradiction appears to be the drop in the use of TLS for sending the spam.

TLS makes use of an encrypted connection to send the messages and botherders may have believed this would decrease the chances of their messages being intercepted; in April, 30% of all spam and 70% of Rustock spam was send using TLS. However, TLS significantly slows down the connection, and with now less than 0.2% of spam being sent over TLS connections, spammers seem to have realised that their delivery rates were being significantly impacted by its use.

Currently 92.2% of all email is spam - an increase of 3.3% since July; 95% of these spam messages are sent via botnets. The relatively low spam ratio in July is explained by a temporary drop in spam coming from a number of botnets, most notable the Grum botnet.

In August, Grum's output increased again and it now takes up second position among the most prolific spamming botnets, with over 16% of spam sent through its bots. While Rustock has mostly infected computers in Western countries, Grum's bots are more likely to be found in Russia, India and Vietnam.

The full MessageLabs report can be found here (PDF), with comments on how this affects those sending legitimate email at the Word to the Wise blog here.

Posted on 26 August 2010 by Virus Bulletin



Latest posts:

VB2019 paper: APT cases exploiting vulnerabilities in region-specific software

At VB2019, JPCERT/CC's Shusei Tomonaga and Tomoaki Tani presented a paper on attacks that exploit vulnerabilities in software used only in Japan, using malware that is unique to Japan. Today we publish both their paper and the recording of their…

New paper: Detection of vulnerabilities in web applications by validating parameter integrity and data flow graphs

In a follow-up to a paper presented at VB2019, Prismo Systems researchers Abhishek Singh and Ramesh Mani detail algorithms that can be used to detect SQL injection in stored procedures, persistent cross-site scripting (XSS), and server‑side request…

VB2020 programme announced

VB is pleased to reveal the details of an interesting and diverse programme for VB2020, the 30th Virus Bulletin International Conference.

VB2019 paper: Cyber espionage in the Middle East: unravelling OSX.WindTail

At VB2019 in London, Jamf's Patrick Wardle analysed the WindTail macOS malware used by the WindShift APT group, active in the Middle East. Today we publish both Patrick's paper and the recording of his presentation.

VB2019 paper: 2,000 reactions to a malware attack – accidental study

At VB2019 cybercrime journalist and researcher Adam Haertlé presented an analysis of almost 2000 unsolicited responses sent by victims of a malicious email campaign. Today we publish both his paper and the recording of his presentation.

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.