CVE-2024-1086: Linux Kernel Privilege Escalation Flaw

CVE-2024-1086 Overview

A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achieve local privilege escalation. The nft_verdict_init() function allows positive values as drop error within the hook verdict. As a result, the nf_hook_slow() function can cause a double free vulnerability when NF_DROP is issued with a drop error that resembles NF_ACCEPT.

Critical Impact

This vulnerability allows attackers to escalate privileges locally through a crafted sequence of system calls.

Affected Products

• Linux Kernel
• Fedoraproject Fedora
• Redhat Enterprise Linux Desktop

Discovery Timeline

• Published Date - CVE-2024-1086 published to NVD
• Last Modified Date - Last updated in NVD database

Technical Details for CVE-2024-1086

Vulnerability Analysis

The vulnerability is a result of improper handling of drop errors in the nft_verdict_init() function. This oversight allows an attacker to trigger a double free scenario, leading to a potential elevation of privileges.

Root Cause

The root cause lies in the mishandling of error codes in the nft_verdict_init() function, which paves the way for unintended memory operations.

Attack Vector

This is a local vulnerability, exploitable by an attacker with local access and the ability to execute crafted binaries.

// Example exploitation code (sanitized)
#include <stdio.h>
#include <stdlib.h>

void trigger_vulnerability() {
    /* Code to initialize and exploit the NFT netfilter issue */
    // Simulated payload causing the use-after-free condition
}

int main() {
    trigger_vulnerability();
    return 0;
}

Detection Methods for CVE-2024-1086

Indicators of Compromise

• Unusual kernel panic logs
• Unexpected reboots
• Altered system binaries

Detection Strategies

Implement monitoring for anomalous activity in kernel netfilter operations and review crash logs for signs of exploitation.

Monitoring Recommendations

Use kernel audit tools to capture events related to netfilter operations. Correlate with system call logs to identify suspicious activity patterns.

How to Mitigate CVE-2024-1086

Immediate Actions Required

• Upgrade the Linux kernel to the patched version.
• Monitor systems for unusual activity.
• Regularly review system and audit logs.

Patch Information

Apply the patch available at: Kernel Patch

Workarounds

Reconfigure affected services to minimize exposure and restrict unauthorized actions.

# Configuration example
sudo systemctl stop nftables
sudo systemctl mask nftables