OpenSSH SSHd SIGALRM Race Enables Remote RCE
CVE-2024-6409 Published on July 8, 2024
Openssh: possible remote code execution due to a race condition in signal handling affecting red hat enterprise linux 9
A race condition vulnerability was discovered in how signals are handled by OpenSSH's server (sshd). If a remote attacker does not authenticate within a set time period, then sshd's SIGALRM handler is called asynchronously. However, this signal handler calls various functions that are not async-signal-safe, for example, syslog(). As a consequence of a successful attack, in the worst case scenario, an attacker may be able to perform a remote code execution (RCE) as an unprivileged user running the sshd server.
Vulnerability Analysis
CVE-2024-6409 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public. 7 days later.
Weakness Type
Signal Handler Race Condition
The software uses a signal handler that introduces a race condition.
Products Associated with CVE-2024-6409
You can be notified by email with stack.watch whenever vulnerabilities like CVE-2024-6409 are published in these products:
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.