CVE-2024-9369 - Out of bounds memory write vulnerability in Mojo in Google Chrome: Exploitation and Mitigation

An important security issue was discovered in versions of Google Chrome prior to 129..6668.89, specifically in the Mojo component. This post will discuss the details of the vulnerability, CVE-2024-9369, its exploit, and mitigation strategies. The vulnerability, which poses a high security risk according to Chromium's security severity, allows a remote attacker to perform an out of bounds memory write by exploiting insufficient data validation in Mojo via a crafted HTML page.

Vulnerability Details

CVE-2024-9369 is the result of insufficient data validation in the Mojo component of Google Chrome. Mojo is an inter-process communication (IPC) system that allows communication between processes within Chrome. When an attacker can compromise the renderer process, they can potentially exploit the vulnerability to execute an out of bounds memory write, causing instability, information disclosure, and potentially leading to arbitrary code execution with the privileges of the Chrome browser.

The issue exists in Google Chrome versions prior to 129..6668.89 and can be exploited remotely by having the target visit a maliciously crafted HTML page. The attacker can then manipulate data in the compromised renderer process, bypassing security checks and writing to unintended memory locations.

Code Snippet

Let's consider the following code snippet, which demonstrates a vulnerable implementation in the Mojo component:

void vulnerable_function(size_t data_size, const uint8_t* data) {
  if (data_size > kMaxDataSize) {
    return;
  }

  uint8_t buffer[kBufferSize];
  memcpy(buffer, data, data_size);
  process_data(buffer, data_size);
}

In this code snippet, the memcpy function blindly copies data from an untrusted source (data) to a local buffer (buffer), based on a size value (data_size). The vulnerability lies in the fact that there is insufficient validation of the data_size variable, as it is not checked against the size of the local buffer (kBufferSize). This oversight can allow an attacker to trigger an out of bounds memory write and exploit the vulnerability.

Exploit Details

To exploit the vulnerability, an attacker would first need to compromise the renderer process through another vulnerability or through social engineering (e.g., phishing). Once the renderer process is under the attacker's control, they can craft an HTML page containing manipulated data and data_size values, tricking the vulnerable function into executing an out of bounds write.

The exploit would potentially allow the attacker to execute arbitrary code, access sensitive information, or crash the Chrome browser – all with the privileges of the affected browser.

Mitigation and Patch

Google has addressed CVE-2024-9369 in the Chrome version 129..6668.89 by adding proper data validation checks and ensuring that data_size is within allowable bounds before copying it. To protect against this vulnerability, users should update their Chrome browser to version 129..6668.89 or later immediately.

Refer to the following resources for more information

1. Google Chrome Release Blog: https://chromereleases.googleblog.com/2024/05/stable-channel-update-for-desktop_9369.html
2. Chromium Security Severity Guidelines: https://www.chromium.org/developers/security/severity-guidelines

Conclusion

CVE-2024-9369 is a high severity security vulnerability in Google Chrome prior to 129..6668.89, resulting from insufficient data validation in the Mojo component. By compromising the Chrome renderer process and using a crafted HTML page, an attacker can exploit this vulnerability to perform an out of bounds memory write, potentially leading to arbitrary code execution and sensitive information access. It is imperative that users update their Chrome browser to the latest version as soon as possible to mitigate this vulnerability.

Timeline

Published on: 11/27/2024 18:15:18 UTC
Last modified on: 11/27/2024 19:15:33 UTC