CVE-2008-3466: Microsoft Host Integration Server RPC authentication bypass enables command execution

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 18 September 2026. Confidence: high.

critical priorityUnauthenticated remote code execution with a CVSS 2.0 score of 10, very high EPSS, and public exploit references make this an urgent patch-or-isolate case.

What it is

Microsoft Host Integration Server 2000, 2004, and 2006 fails to restrict RPC access to administrative functions, allowing remote attackers to bypass authentication and invoke the CreateProcess function through crafted SNA RPC messages using opcode 1 or 6. This is a pre-authentication remote code execution flaw in a server product, so any reachable HIS RPC endpoint is a direct path to full host compromise.

Impact

An unauthenticated remote attacker can execute arbitrary programs on the affected server, gaining the privileges of the HIS service and effectively full control of the host. No user interaction or valid credentials are required.

Attack surface

Reached over the network via the SNA RPC interface exposed by Host Integration Server; the CVSS vector AV:N/AC:L/Au:N confirms no authentication and no user interaction are needed. Any host that can route to the HIS RPC endpoint can attempt the attack.

Exploitation

Not listed in CISA KEV, but EPSS is very high (0.777 probability, 99.5th percentile) and a SecurityFocus reference carries an Exploit tag, indicating public exploit material exists. No ransomware group use is documented in the record.

What to do

• Apply Microsoft security bulletin MS08-059 (the vendor patch) to all HIS 2000, 2004, and 2006 installations immediately.
• Restrict network access to HIS SNA RPC ports with host and perimeter firewalls so only trusted management hosts can reach them.
• If HIS is not required, decommission or disable the service; otherwise isolate affected servers on a segmented management network.
• Monitor for and block unexpected SNA RPC traffic, particularly messages using opcode 1 or 6, at network boundaries.
• Verify patch status with the OVAL definition for CVE-2008-3466 and re-scan after remediation.

Detection

• Alert on SNA RPC messages containing opcode 1 or 6 directed at HIS servers from unexpected source addresses.
• Monitor HIS service and system process creation for unexpected child processes such as cmd.exe or other executables spawned by the HIS process.
• Baseline and audit network flows to HIS RPC ports, flagging new or external sources.
• Correlate Windows event logs for service account activity with anomalous process creation on HIS hosts.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.