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Cisco patches latest IOS security hole

Bill Brenner, Senior News Writer

Cisco Systems Inc. has issued a patch for its Internetwork Operating System (IOS), closing a security hole attackers could use to bypass command authorization checks and gain escalated user privileges.

The

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vulnerability exists within the IOS Authentication, Authorization, and Accounting (AAA) command authorization feature, "where command authorization checks are not performed on commands executed from the Tool Command Language (Tcl) exec shell," Cisco said in its advisory. "This may allow authenticated users to bypass command authorization checks in some configurations, resulting in unauthorized privilege escalation."

The vulnerability affects IOS version 12.0T or later. Cisco said devices that don't run the AAA command authorization feature or don't support Tcl functionality are not affected by the flaw.

The San Jose, Calif.-based networking giant also warned that an authenticated user is automatically placed into the Tcl shell mode if a previous user goes into Tcl shell mode and terminates the session before leaving the Tcl shell mode. This could exacerbate the vulnerability, the company said.

The patch is the latest in a series of steps Cisco has taken to address security holes in the past week.

It patched two security holes in CallManager -- the software-based call-processing component of its IP telephony products -- and offered workarounds for a glitch in the (IOS) HTTP Server.