CISA Warns of Linux Kernel Use-After-Free Vulnerability Exploited in Attacks to Deploy Ransomware
Overview:
CISA has issued an urgent alert regarding CVE-2024-1086, a use-after-free vulnerability in the Linux kernel’s netfilter: nf_tables component. The flaw allows local attackers to escalate privileges to root, enabling ransomware deployment and full system compromise.
Initially disclosed in early 2024, this vulnerability is now confirmed to be actively exploited in the wild, with attacks targeting unpatched Linux servers across enterprise, cloud, and IoT environments.
Reports indicate the vulnerability is being leveraged by threat actors to deploy ransomware families such as LockBit and Conti variants, following initial access gained through phishing or credential abuse.
Who it Impacts:
- 1. Organizations running unpatched Linux distributions including:
- Ubuntu 20.04 / 22.04 LTS
- Red Hat Enterprise Linux (RHEL) 8 / 9
- Debian 11 / 12
- Other distributions using kernels prior to version 6.1.77
How it Impacts:
The flaw lies in the nf_tables (netfilter) subsystem of the Linux kernel, which manages firewall and packet filtering rules.
- During nftables rule evaluation, the kernel improperly frees memory associated with a network table but fails to nullify the pointer.
- An attacker crafts malicious nftables rules to reuse the freed memory, exploiting the dangling pointer to execute arbitrary code in kernel space.
- Once triggered, this leads to local privilege escalation to root.
- Attackers then deploy ransomware payloads, encrypting files and disabling logs or defenses.
CVE Details:
| CVE | CVE-2024-1086 |
| Severity | High |
| CVSS | 7.8 |
Recommendations:
- Upgrade to Linux kernel version 6.1.77 or higher, or apply vendor-specific security updates
- If patching is delayed, disable nf_tables if not required and Restrict local shell access and limit sudo privileges.
Conclusion:
CVE-2024-1086 poses a severe threat to Linux-based infrastructures, with confirmed ransomware exploitation in the wild. Attackers are chaining this vulnerability with phishing and credential theft to gain full system control and deploy ransomware payloads. Organizations must patch immediately, enhance kernel-level monitoring, and restrict local privileges to reduce exposure. Delaying remediation significantly increases the risk of operational disruption and data loss.
Reference Links:
https://cybersecuritynews.com/linux-kernel-use-after-free-vulnerability-exploited/
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-1086