While investigating a major surge in Gumblar-related compromises, ScanSafe STAT security researcher Gregg Conklin noticed that some of the compromises were following a different pattern than we'd been seeing over the past couple of weeks. Further investigation revealed the newest iframe injection was pointing once again to gumblar.cn - the malware domain that originally earned Gumblar its name.

The domain's reactivation occurred less than 24 hours ago, but it has ramifications that could stretch back for months. Any sites compromised in the May Gumblar attacks that were not yet cleaned up (unfortunately an all-to-common occurrence) could now start becoming vectors of Gumblar infection once again. This is in addition to new compromises pointing to the newly activated gumblar.cn and the already very active Gumblar compromises which are using compromised websites as malware hosts.

It's a mess. Stay tuned.

Edited to add: This is not the first example of registrars releasing malware domain names back into use. ScanSafe brought this to the publics' attention in June 2008. For details, see Registrars Release Suspended Domains to Attackers.