Ciscos Security Timeout and Kerberos Critical Crack

Opinion: Cisco times out VOIP denial-of-service, while MIT melts down over "highly critical" Kerberos vulnerabilities. If you have Cisco's CallManager, ONS 15216 OADM and Security Agent, you really need to go get some patches from them.

If the latest boatload of patches from Redmond and San Jose werent enough for you (as well as anything important that had to run no matter what, patches be damned) this week, there was enough other stuff happening for other vendors to make things interesting.

If you have Ciscos CallManager, ONS 15216 OADM and Security Agent, you really need to go get some patches from them.

The holes can lead to denial-of-service attacks and malicious code execution. In short, the problem is that with out the patches, any arbitrary IP device that is connected to the Call Manager (which controls how the network extends to packet devices) hose you big time. Not fun.

But the sploit I really liked involved the network ports.

RISDC (Realtime Information Server Data Collection) sockets were evidently not timed out aggressively enough allowing "RisDC.exe" to consume large amounts of memory and ports and eventually fall off the Earth.

I keep wondering if this kind of attack is just a variant of any other DoS that induces unrecoverable (without reboot) errors, or there is something new here because of how it injects itself. Of course, it may just be that Cisco made the timeouts too long.

On the other hand, port timeouts are pretty standard design decisions. So is listening time.

I wonder if aggressively timing out the sockets wont induce an increase in operational refuse/retry loops, affecting throughput at the packet level. This bears watching.

Cuts Like a Knife

Kerberos, the authentication method developed at MIT and used primarily by Sun, was revealed by those wacky Danes at Secunia this week to have "highly critical" security holes.

In shame, the entire MIT campus committed en mass ritual disembowelment as a means of atonement.

Since only migrant day workers involved in cleaning the halls were around on a hot summer day, the institution will carry on.

As a token of respect, the remains were stolen by undergraduates and placed on top of the Dome as a prank.

Secunias advisory laid out many problems, but the first one was a doozy.

/zimages/6/28571.gifClick here to read more about the Kerberos flaws.

"A double-free error in the krb5_recvauth () function can potentially be exploited to execute arbitrary code in the context of the program calling this function," Secunia said.

"Successful exploitation may lead to the compromise of an entire Kerberos realm or cause the program to crash." Taking down a realm gets my attention.

Another one is that the Key Distribution Center (before 1.4.1) can be crashed by TCP requests (not the "specially crafted" TCP packet weve all come to know and love, just a "specially crafted" request).

Memory management issues and heap protection seem to be the culprits.

There are patches available from the Kerberos Team, and 1.4.2 will embed the fixes.

Larry Loeb was consulting editor for BYTE magazine and senior editor of WebWeek. He serves as a subject matter expert for the Department of Defenses Information Assurance Technology Analysis Center, and is on the American Dental Associations WG-1 and MD 156 electronic medical records working groups. Larrys latest book is "Hackproofing XML," published by Syngress (Rockland, Mass.). If youve got a tip for Larry, contact him at

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