Fake updates and phony postcards carry malware

Microsoft patch and greetings card spams bring more trojans.

Several spam runs posing as vulnerability alerts from Microsoft have been spotted in the last week, with links to supposed patches in fact leading to malware downloads. Since then, a resurgence of the trojans dubbed the 'Storm Worm', seeded in several waves earlier in the year, has also been bombarding inboxes around the globe.

The fake Microsoft alerts have all referred to bogus Security Bulletins, a tactic not helped by the release of a genuine bulletin last week. Most of the emails spammed out have been reasonably easy to spot, however, with the usual poor spelling and grammar giving the game away. Microsoft has also pointed out that it never includes direct links to download executables in its alerts.

Over the weekend, several runs of variants of the 'Storm Worm' have been spammed out, continuing into today, with subject lines promising 'ecards' or 'greetings cards', and some using links resembling those used by semi-legitimate greeting card sites, but the downloaded files are typically variants of the Peacomm/Nuwar/Luder/Dorf malware which made considerable headlines earlier in the year, starting shortly after Christmas with references to major storms in Europe as lures.

The latest variants are being spammed out and hosted by systems infected in previous runs, and attacks include techniques to adjust vulnerabilities used to infiltrate systems based on which browsers are thought to be in use.

Suggestions have been made that the latest run is a response to the Mpack-based outbreaks centring on Italy recently, which have been known to disable or uninstall Storm-type malware, while Storm zombies have apparently been involved in DDoS attacks on the Mpack-ware seed sites, according to a report in The Register.

More details of the Microsoft bulletin spams can be found here (from Sophos) or here (from Mary Landesman at About.com), while Storm worm info is here (from SANS Internet Storm Center) or here (from McAfee). SANS also has some follow-up information on sites compromised to carry Mpack-created malware in the recent attack, here.