CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel's TCP conntrack state machine allows an attacker to force a connection into the CLOSE state using a crafted RST packet with an invalid sequence number, potentially disrupting active NAT entries. This flaw can lead to premature connection termination, undermining the integrity of network communications. Organizations using affected Linux systems, particularly those relying on NAT for traffic management, should prioritize patching to mitigate this high-severity risk.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: tcp: do not force CLOSE on invalid-seq RST without direction check An unintended behavior in the TCP conntrack state machine allows a connection to be forced into the CLOSE state using an RST packet with an invalid sequence number. Specifically, after a SYN packet is observed, an RST with an invalid SEQ can transition the conntrack entry to TCP_CONNTRACK_CLOSE, regardless of whether the RST corresponds to the expected reply direction. The relevant code path assumes the RST is a response to an outgoing SYN, but does not validate packet direction or ensure that a matching SYN was actually sent in the opposite direction. As a result, a crafted packet sequence consisting of a SYN followed by an invalid-sequence RST can prematurely terminate an active NAT entry. This makes connection teardown easier than intended. So, tighten the state transition logic to ensure that RST-triggered CLOSE transitions only occur when the RST is a valid response to a previously observed SYN in the correct direction.