Storm e-card malware keeps on coming

No end to flood of fake friendly greetings.

A further wave of e-cards carrying links to 'Storm' malware (various labelled Nuwar, Peacomm, Dorf, Zhelatin) has been hitting inboxes around the world all this week, with no signs of any letup in the deluge.

The latest barrage carry a simple message, using spoofed source addresses and claiming to originate from a friend, colleague or family member. The plain text mails carry a link to a 'greeting' left at a site whose name is selected from a long list of likely titles for such greetings systems, usually also including copyright information matching the selected site title. Following the link leads to one of the same botnet of compromised systems which have been spamming out the mails, hosting a site using exploits to attempt a drive-by download or, if visited by systems lacking the required vulnerabilities, simply presenting a link to download the executable.

The trojans are regularly repacked at the server side to minimise detection by anti-malware products, with tens of thousands of unique variants being spotted by analysis labs. Malware watchers have speculated that as many as 250,000 zombie systems may be hosting the attack sites, making blocking the source domains a similarly enormous task, while spam counters at Sophos have reported seeing 9 million greetings card spams in a 48-hour period.

On the McAfee Avert Labs blog this week, Dmitri Gryaznov details his home-brewed system for keeping up with the constant changes in source and content, here, while Alyssa Myers speculates about the impact of the series of spam campaigns on the genuine greetings card industry, here. Some more details of the latest techniques are at F-Secure, here.

The potential of the 'Storm' botnet for launching major DDoS attacks has also resurfaced. A group of security admins in the world of academia, thought to be at particular risk at this time of year as large numbers of new students take up new accounts on university networks, has been warned of a risk of attacks from the Storm cloud, after probing infected machines for related vulnerabilities was seen to bring on attacks on the scanning system. The warning, issued by the REN-ISAC collaborative research group, is here.

17 August 2007

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