[Snort-sigs] Denial of Service (DoS) in Microsoft SMS Client Signature
terencerunge at ...1224...
Wed Jul 14 14:02:22 EDT 2004
In reference to the SMS Client DoS made public on Full Disclosure today
I put together a quick signature. Please modify / improve at will.
alert tcp any any -> $HOME_NET 2702 (msg:"SMS Client DoS Attempt";
classtype:attempted-dos; sid:7130410; rev:1;)
Denial of Service (DoS) in Microsoft SMS Client
Microsoft Systems Management Server provides configuration management
solution for Windows platform. It is widely deployed in medium and large
network environments. A flaw in SMS Remote Control service makes possible to
crash the service remotely leading to the DoS condition.
All tests were performed on a client part of Microsoft Systems Management
Server version 2.50.2726.0.
Cause and Effect:
SMS Remote Control Client service is listening on TCP ports 2701 and 2702.
The service performs basic signature checks and size tests on received data
and assumes the data is correct if those tests pass. It is possible to
a data packet that will go through basic checks and throw an exception by
causing the server to read or write to an invalid memory address. It is also
possible to specify the memory address value in the data packet.
Initial analysis showed that the problem is not [easily] exploitable because
there is no buffer overflow condition and it is not possible to specify the
data to be written to the memory. The exception occurs in multprot.dll
library when the service makes an API call with invalid parameters.
The problem can be reproduced by sending the "RCH0####RCHE" string
a large number of characters (over 130) to TCP port 2702.
At the time of release vendor was not aware of the vulnerability.
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or more detailed analysis may obtain more information by writing to the
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