Headline
FreeBSD Releases Urgent Patch for High-Severity OpenSSH Vulnerability
The maintainers of the FreeBSD Project have released security updates to address a high-severity flaw in OpenSSH that attackers could potentially exploit to execute arbitrary code remotely with elevated privileges. The vulnerability, tracked as CVE-2024-7589, carries a CVSS score of 7.4 out of a maximum of 10.0, indicating high severity. "A signal handler in sshd(8) may call a logging function
Cybersecurity / Network Security
The maintainers of the FreeBSD Project have released security updates to address a high-severity flaw in OpenSSH that attackers could potentially exploit to execute arbitrary code remotely with elevated privileges.
The vulnerability, tracked as CVE-2024-7589, carries a CVSS score of 7.4 out of a maximum of 10.0, indicating high severity.
“A signal handler in sshd(8) may call a logging function that is not async-signal-safe,” according to an advisory released last week.
“The signal handler is invoked when a client does not authenticate within the LoginGraceTime seconds (120 by default). This signal handler executes in the context of the sshd(8)'s privileged code, which is not sandboxed and runs with full root privileges.”
OpenSSH is an implementation of the secure shell (SSH) protocol suite, providing encrypted and authenticated transport for a variety of services, including remote shell access.
CVE-2024-7589 has been described as an “another instance” of a problem that’s referred to as regreSSHion (CVE-2024-6387), which came to light early last month.
“The faulty code in this case is from the integration of blacklistd in OpenSSH in FreeBSD,” the project maintainers said.
“As a result of calling functions that are not async-signal-safe in the privileged sshd(8) context, a race condition exists that a determined attacker may be able to exploit to allow an unauthenticated remote code execution as root.”
Users of FreeBSD are strongly advised to update to a supported version and restart sshd to mitigate potential threats.
In cases where sshd(8) cannot be updated, the race condition issue can be resolved by setting LoginGraceTime to 0 in /etc/ssh/sshd_config and restarting sshd(8). While this change makes the daemon vulnerable to a denial-of-service, it safeguards it against remote code execution.
Found this article interesting? Follow us on Twitter and LinkedIn to read more exclusive content we post.
Related news
Quay.io is Red Hat’s hosted container registry service that serves enterprise users, open source community projects, and Red Hat customers worldwide. One of the most used features of Quay.io, besides storing and serving container images, is the comprehensive security vulnerability reporting for any uploaded image. Because Red Hat is committed to making open source software more accessible, this functionality is also available on the free tier, provided by the Clair static vulnerability analyzer project.Clair allows users to analyze millions of container images and billions of layers, and pr
Select versions of the OpenSSH secure networking suite are susceptible to a new vulnerability that can trigger remote code execution (RCE). The vulnerability, tracked as CVE-2024-6409 (CVSS score: 7.0), is distinct from CVE-2024-6387 (aka RegreSSHion) and relates to a case of code execution in the privsep child process due to a race condition in signal handling. It only impacts versions 8.7p1
Red Hat Security Advisory 2024-4312-03 - An update for openssh is now available for Red Hat Enterprise Linux 9. Issues addressed include a code execution vulnerability.
Gentoo Linux Security Advisory 202407-9 - A vulnerability has been discovered in OpenSSH, which can lead to remote code execution with root privileges. Versions greater than or equal to 9.7_p1-r6 are affected.
Ubuntu Security Notice 6859-1 - It was discovered that OpenSSH incorrectly handled signal management. A remote attacker could use this issue to bypass authentication and remotely access systems without proper credentials.
Debian Linux Security Advisory 5724-1 - The Qualys Threat Research Unit (TRU) discovered that OpenSSH, an implementation of the SSH protocol suite, is prone to a signal handler race condition. If a client does not authenticate within LoginGraceTime seconds (120 by default), then sshd's SIGALRM handler is called asynchronously and calls various functions that are not async-signal-safe. A remote unauthenticated attacker can take advantage of this flaw to execute arbitrary code with root privileges. This flaw affects sshd in its default configuration.
Qualys has discovered a a signal handler race condition vulnerability in OpenSSH's server, sshd. If a client does not authenticate within LoginGraceTime seconds (120 by default, 600 in old OpenSSH versions), then sshd's SIGALRM handler is called asynchronously, but this signal handler calls various functions that are not async-signal-safe - for example, syslog(). This race condition affects sshd in its default configuration.
OpenSSH maintainers have released security updates to contain a critical security flaw that could result in unauthenticated remote code execution with root privileges in glibc-based Linux systems. The vulnerability has been assigned the CVE identifier CVE-2024-6387. It resides in the OpenSSH server component, also known as sshd, which is designed to listen for connections from any of the client