MS Host Integration Server Memory Corruption

June 10, 2011

Microsoft Host Integration Server (a.k.a. HIS) is a gateway application providing connectivity between Microsoft Windows networks and IBM mainframe and AS/400 systems. Support is provided for SNA, 3270 (standard and Telnet 3270 TN3270E), 5250 (standard and Telnet 5250), CICS, APPC, and other IBM protocols. Support is also provided for advanced integration with Windows networks and software, such as linking Microsoft Message Queuing applications to IBM WebSphere MQ, binding Microsoft DTC transactions with CICS, and cross-protocol access to DB2 databases on IBM platforms. HIS is the successor to Microsoft SNA Server.

The Systems Network Architecture (SNA) communication protocol is a proprietary undocumented protocol, although it is still in wide use in the banking industry and various government agencies. Microsoft HIS deploys a number of services to handle the SNA protocol. By observing the traffic data, the following information can be deduced for the UDP traffic of snalink.exe, snaservr.exe and mngagent.exe services.

Offset Size (bytes) Description
0x00 2 payload size (starting at offset 0x39)
0x02 1 opcode
0x03 16 Unknown hostname (possibly source)
0x13 1 0x2a
0x14 15 Unknown
0x23 16 Unknown hostname (possibly destination)
0x33 6 Unknown
0x39 payload size payload

A denial of service vulnerability exists in Microsoft Host Integration Server. The vulnerability is due to an input validation error while parsing messages with a special opcode. A remote, unauthenticated attacker can exploit this vulnerability by sending a specially crafted packet to any of the vulnerable services. This can lead to a denial of service condition.

SonicWALL UTM has researched and analyzed the vulnerability. The following IPS signatures has been created to detect/prevent the malicious traffic.

  • 6703 MS Host Integration Server Memory Corruption