Virus writers have created the first worm that targets a Windows vulnerability (MS05-051) patched by Microsoft in October. The Dasher-A worm is based on exploit code released at the start of December but coding mistakes and reliance on a currently unavailable server in China mean the malware isn't able to spread.

Samples of the code were sent to anti-virus firms, a common enough tactic among amateur virus authors though less common these days since endless variants of established worms and Trojans have become the order of the day. Dasher-A isn't a threat but it does show virus writers are continuing to sniff around Windows vulnerabilities, a fact sometimes obscured by the dominance of Sober and NetSky variants in recent viral charts. The MS05-051 patch, which fixes flaws with certain Windows middleware components, was the subject of early glitches even after warnings that it was ripe for malware exploitation, so its interest to VXers comes as no great surprise. ®

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