Rule Document 1:67155

Rule Category

PROTOCOL-RPC -- Snort has detected traffic that may indicate the presence of the rpc protocol or vulnerabilities in the rpc protocol on the network.

Alert Message

PROTOCOL-RPC FreeBSD NFS RPCSEC_GSS stack buffer overflow attempt

Rule Explanation

This rule looks for a malformed RPCSEC_GSS authentication packet sent to a vulnerable FreeBSD system.

What To Look For

This rule looks for attempts to exploit a buffer overflow vulnerability in the RPCSEC_GSS authentication of the kgssapi.ko module in FreeBSD systems.

Known Usage

Attacks/Scans seen in the wild

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

MITRE::ATT&CK Framework::Enterprise::Initial Access::Exploit Public-Facing Application

Adversaries may attempt to take advantage of a weakness in an Internet-facing computer or program using software, data, or commands in order to cause unintended or unanticipated behavior. The weakness in the system can be a bug, a glitch, or a design vulnerability. These applications are often websites, but can include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other applications with Internet accessible open sockets, such as web servers and related services.

Rule Categories::Protocol::RPC

Vulnerability::Severity::High

Vulnerability::Severity::Critical

CVE

CVE-2026-4747

Additional Links

www.freebsd.org/security/advisories/FreeBSD-SA-26:08.rpcsec_gss.asc

Rule Vulnerability

Memory Corruption

Memory Corruption is any vulnerability that allows the modification of the content of memory locations in a way not intended by the developer. Memory corruption results are inconsistent; they could lead to fatal errors and system crashes or data leakage; some have no effect at all.

CVE Additional Information

This product uses data from the NVD API but is not endorsed or certified by the NVD.

CVE-2026-4747

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