CVE-2023-6040: Out-of-Bounds Access Vulnerability in Netfilter

Overview

The cybersecurity landscape continues to face new challenges with the discovery of the CVE-2023-6040 vulnerability, an out-of-bounds access issue involving netfilter. This vulnerability affects systems employing the netfilter technology, which is particularly used in Linux distributions for packet filtering, network address translation, and port translation.
The CVE-2023-6040 vulnerability poses a severe threat due to its potential for system compromise and data leakage. This could have disastrous consequences, especially for organizations dealing with sensitive data, as it could lead to unauthorized data access and malicious activities within the compromised system.

Vulnerability Summary

CVE ID: CVE-2023-6040
Severity: High (7.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Linux Kernel | Versions prior to f1082dd31fe4

How the Exploit Works

The vulnerability stems from an issue within the `nf_tables_newtable` function. While creating a new netfilter table, there is a lack of safeguard against invalid nf_tables family (pf) values. This oversight enables an attacker to supply invalid pf values, leading to out-of-bounds access. This out-of-bounds access could then be exploited to execute arbitrary code, alter system functionality, or access sensitive data, leading to potential system compromise or data leakage.

Conceptual Example Code

Consider the following conceptual pseudocode to understand the potential exploitation:

#include <linux/netfilter.h>
void exploit_vulnerability() {
struct nft_table *table;
u8 invalid_family_value = 0xFF; // Invalid family value
// Create a new netfilter table with an invalid family value
table = nf_tables_newtable(invalid_family_value, ...);
// Leverage out-of-bounds access for malicious activity
do_malicious_activity(table);
}

In this hypothetical example, an attacker could use an invalid family value to create a new netfilter table. The resulting out-of-bounds access could then be used for malicious activities, potentially leading to system compromise or data leakage.
Given the severity of this vulnerability, it is highly recommended to apply any available vendor patches or use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as a temporary mitigation measure.