Old Linux Kernel flaw CVE-2024-1086 resurfaces in ransomware attacks

CISA warns ransomware gangs exploit CVE-2024-1086, a Linux kernel flaw in netfilter: nf_tables, introduced in 2014 and patched in Jan 2024.

CISA warned that ransomware gangs are exploiting CVE-2024-1086, a high-severity Linux kernel flaw introduced in 2014 and patched in January 2024.

CISA didn’t provide details about the ransomware attacks exploiting the flaw or name the groups responsible for targeting it.

The vulnerability CVE-2024-1086 is a Linux kernel use-after-free issue that resides in the netfilter: nf_tables component that allows an attacker to achieve local privilege escalation.

In March 2024, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) added the flaw to its Known Exploited Vulnerabilities (KEV) catalog after the researcher “Notselwyn” published a detailed analysis and PoC exploit for the issue.

“When you try to reproduce the bug yourselves, the kernel may panic, even when all mitigations are disabled. This is because certain fields of the skb – such as pointers – get corrupted when the skb is freed. As such, we should try to avoid usage of these fields.” wrote Notselwyn. “Fortunately, I found a way to bypass all usage which could lead to a panic or usual errors and get a highly reliable double-free primitive. I’m highlighting this in the respective subsection within the proof-of-concept section.”

The researchers demonstrated local privilege escalation on Linux kernels 5.14–6.6. The flaw affects major distributions like Debian, Ubuntu, Fedora, and Red Hat, impacting kernel versions from 3.15 up to 6.8-rc1.

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Pierluigi Paganini

(SecurityAffairs – hacking, CISA)