Cisco has warned its customers that many of its routers are vulnerable to a new malware tactic.

Drive-by pharming, a technique identified by researchers from Symantec and Indiana University, involves luring users to malicious sites where a device's default password is used to redirect them to bogus sites. Once they are at those sites, their identities could be stolen or malware could be force-fed to their computers.

In an advisory, Cisco listed 77 vulnerable routers in the lines sold to small offices, home offices, branch offices and telecommuters. The advisory recommended that users change the default username and password required to access the router's configuration settings, and disable the device's HTTP server feature.

The paper that identified the technique urged a similar move by router owners. "Owners of home routers who set a moderately secure password - one that is non-default and non-trivial to guess -- are immune to router manipulation via JavaScript," it said.

The researchers also argued that router makers should stop using blank or easy-to-guess passwords, such as "admin," and switch to the device's serial number. "This value, which is unique to each individual router, would comprise a very secure and unpredictable password," the report stated.

Original story by Computerworld US