CVE-2024-6409 Openssh: possible remote code execution due to a race condition in signal handling affecting red hat enterprise linux 9

High 7.0 Published Updated

A race condition in OpenSSH's signal handling allows remote attackers to achieve code execution as an unprivileged user.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2024-6409?

CVE-2024-6409 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 8 Jul 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-364

Which versions are affected by CVE-2024-6409?

Linux distribution packages (40)
openssh AlmaLinux:9All versions8.7p1-38.el9_4.4
openssh-askpass AlmaLinux:9All versions8.7p1-38.el9_4.4
openssh-clients AlmaLinux:9All versions8.7p1-38.el9_4.4
openssh-keycat AlmaLinux:9All versions8.7p1-38.el9_4.4
openssh-server AlmaLinux:9All versions8.7p1-38.el9_4.4
pam_ssh_agent_auth AlmaLinux:9All versions0.10.4-5.38.el9_4.4
openssh-askpass Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-askpass-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-clients-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-debugsource Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-keycat-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-server-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
openssh-sk-dummy-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:8.7p1-38.el9_4.4
pam_ssh_agent_auth Red Hat:enterprise_linux:9::appstreamAll versions0:0.10.4-5.38.el9_4.4
pam_ssh_agent_auth-debuginfo Red Hat:enterprise_linux:9::appstreamAll versions0:0.10.4-5.38.el9_4.4
openssh Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-askpass-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-clients Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-clients-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-debugsource Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-keycat Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-keycat-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-server Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-server-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
openssh-sk-dummy-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:8.7p1-38.el9_4.4
pam_ssh_agent_auth-debuginfo Red Hat:enterprise_linux:9::baseosAll versions0:0.10.4-5.38.el9_4.4
openssh-askpass Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-askpass-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-clients-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-debugsource Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-keycat-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
openssh-server-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:8.7p1-12.el9_0.3
pam_ssh_agent_auth Red Hat:rhel_e4s:9.0::appstreamAll versions0:0.10.4-4.12.el9_0.3
pam_ssh_agent_auth-debuginfo Red Hat:rhel_e4s:9.0::appstreamAll versions0:0.10.4-4.12.el9_0.3
openssh Red Hat:rhel_e4s:9.0::baseosAll versions0:8.7p1-12.el9_0.3
openssh-askpass-debuginfo Red Hat:rhel_e4s:9.0::baseosAll versions0:8.7p1-12.el9_0.3
openssh-clients Red Hat:rhel_e4s:9.0::baseosAll versions0:8.7p1-12.el9_0.3

How do I fix CVE-2024-6409?

Apply the vendor's patch.

Is CVE-2024-6409 being exploited?

There is no known exploitation of CVE-2024-6409 in the wild and no public exploit code.

Sources

Also known as ALSA-2024:4457, CLSA-2024-1721929402, GHSA-79hg-h6r6-64mm, OESA-2024-1870, OESA-2024-1871, OESA-2024-1872 and 4 more.

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