Malware writers are getting sneakier in their efforts to thwart antivirus solutions, according to a new report from BitDefender Labs.

The research arm of security vendor BitDefender Friday released its list of the top 10 malware threats for September, which revealed that hackers are now crafting attacks that are narrower in focus in order to avoid detection.

Here are the top threats for September, along with the percentage of detections they represent:

BitDefender’s September 2007 Top 10 Malware

1. win32.worm.p2p.puce.g (11.1%)
2. worm.rjump.k (10.3%)
3. win32.worm.autruner.cd (8.4%)
4. win32.netsky.p@mm (6.3%)
5. win32.worm.ice.a (6.1%)
6. win32.worm.rjump.b (5.2%)
7. worm.vbs.solow.a (4.8%)
8. win32.worm.vb.ymeak.a (4.4%)
9. win32.worm.sohanat.as (3.9%)
10. worm.rjump.j (3.5%)