CVE-2024-32913: Remote Code Execution Vulnerability in wl_notify_rx_mgmt_frame of wl

CVE-2024-32913 is a critical remote code execution vulnerability that affects the wl_notify_rx_mgmt_frame function, which is defined in the wl_cfg80211.c file. This vulnerability is due to an integer overflow, which potentially leads to an out-of-bounds write, thereby making it possible for an attacker to execute arbitrary code remotely. User interaction is not required for the exploitation of this vulnerability, and no additional execution privileges are needed.

This blog post aims to provide a detailed explanation of CVE-2024-32913, including code snippets, links to original references, and exploit details. By the end of this post, you'll have a clear understanding of this security vulnerability, its potential impact, and how you can protect your systems from possible exploitation.

Vulnerability Details

The issue resides in the wl_notify_rx_mgmt_frame function, located in wl_cfg80211.c. The function prototype is as follows:

void wl_notify_rx_mgmt_frame(struct bcm_cfg80211 *cfg, void *pktbuf, int total_len)

Here, *cfg is the pointer to the bcm_cfg80211 structure, *pktbuf holds the packet buffer, and total_len refers to the total length of packet data.

An integer overflow occurs when the value of total_len is greater than the maximum possible value of an int data type. In the event of an overflow, the affected calculation wraps around to the smallest possible value, leading to incorrect results.

In this vulnerability, total_len is used as part of a calculation that determines the size of the required memory buffer. Due to the integer overflow, a smaller than needed memory buffer is allocated, leading to an out-of-bounds write when the contents are copied into the buffer.

The following code snippet demonstrates the problematic calculation and allocation

int req_size = total_len + sizeof(bcm_event_t);
char *buf = kzalloc(req_size, GFP_KERNEL);
memcpy(buf, pktbuf, total_len);

Exploit Details

This vulnerability allows a malicious actor to gain unauthorized access to a target system by crafting a specially designed packet that takes advantage of the integer overflow. Once such a packet is received by the target, it is processed by the wl_notify_rx_mgmt_frame function. The packet can cause the integer overflow, resulting in an out-of-bounds write, which may in turn lead to remote code execution without any additional privileges required.

As user interaction is not required for the exploitation of this vulnerability, an attacker could potentially compromise a large number of systems by broadcasting crafted packets.

Original References

1. NVD (National Vulnerability Database) entry for CVE-2024-32913: https://nvd.nist.gov/vuln/detail/CVE-2024-32913
2. CWE (Common Weakness Enumeration) entry for integer overflow: https://cwe.mitre.org/data/definitions/190.html
3. Broadcom official website for wireless drivers: https://www.broadcom.com/support/download-search/

Mitigation Suggestions

To protect your systems from the exploitation of this vulnerability, we recommend taking the following steps:

1. Keep your wireless drivers up to date. Regularly check the Broadcom website or your device manufacturer's website for the latest driver updates.
2. Implement proper input validation and boundary checks in your code to avoid integer overflow vulnerabilities.

Regularly scan your systems for vulnerabilities and apply security patches wherever applicable.

In conclusion, CVE-2024-32913 is a severe security vulnerability that highlights the importance of secure coding practices and the regular updating of software components. Understanding the nature of this vulnerability and taking appropriate remediation actions can greatly reduce the risk of a successful exploitation attempt.

Timeline

Published on: 06/13/2024 21:15:55 UTC
Last modified on: 07/16/2024 14:55:20 UTC