CVE-2022-47673: Binutils addr2line Vulnerability - Exploring the Out-of-Bounds Read in parse_module

Hello everyone!

Today, I want to talk about a recently discovered vulnerability in the Binutils addr2line utility, identified as CVE-2022-47673. This vulnerability exists in versions before 2.39.3 and is caused by multiple out-of-bounds reads in the parse_module function, which can lead to a denial of service or other undefined behaviors.

Binutils, short for Binary Utilities, is an essential collection of tools for working with binary files on Unix-based systems. Among the tools provided is addr2line, which is used to convert addresses into file names and line numbers. It helps programmers identify the location of a problem within their code when debugging.

The issue was discovered by researchers, and they determined that the vulnerability resides in the parse_module function of addr2line. This has the potential to cause a denial of service and other unspecified impacts, including potential memory corruption or information disclosure.

Let's dive a little deeper into the code, explore the issue, and discuss possible exploit scenarios.

The Vulnerable Code Snippet

The vulnerability lies in the parse_module function, which is defined in addr2line.c. The function is responsible for parsing the binary module format. The out-of-bounds read occurs in the following code snippet:

for (i = ; i < info->num_modules; ++i)
{
  const char *p;
  unsigned int len;

  p = read_string (hdrptr);
  if (p == NULL)
    break;

  len = strlen (p) + 1;
  module->name = (char *) xmalloc (len);
  memcpy (module->name, p, len);
  module->text = hdrptr;
  endian_read (uval, hdrptr, hdr_end, 30, 4);
  r = after_end;
  r += uval - dec_bias;
  module->addr = r;
  module->maxaddr = r;

  // ... other code ...
}

The out-of-bounds read occurs when the 'hdrptr' variable is used to access memory that is not within the intended bounds. It can be either before the beginning or after the end of the allocated buffer, and this can result in undefined behavior.

Exploit Details

By exploiting this vulnerability, an attacker can potentially cause a denial of service by crashing the addr2line utility. The undefined behavior may also lead to other impacts, such as memory corruption or information disclosure. The actual exploitability depends on the specific build configuration and environment in which the tool is executed.

Although this is a serious vulnerability, it is important to note that in many practical scenarios, addr2line is run by developers in their local environments during the debugging process. Therefore, the likelihood of an attacker exploiting this vulnerability in a practical setting is comparatively low. However, it's good to be aware of the issue and ensure that you're using a patched version of the software.

For more information on this vulnerability, you can refer to the following resources

1. CVE-2022-47673 - The official CVE entry on MITRE.
2. Binutils Repository - The official repository for the Binutils project.

How to Fix the Issue

To resolve this vulnerability, users are encouraged to update their Binutils package to version 2.39.3 or later, which contains the fix for this issue. Alternatively, you can apply the patch provided by the Binutils maintainers.

For those using a package manager, such as apt or yum, you can usually update Binutils with a simple command:

# For Debian/Ubuntu-based systems
 sudo apt update && sudo apt upgrade

# For CentOS/RHEL-based systems
 sudo yum update

After upgrading to the patched version, your system should no longer be affected by CVE-2022-47673.

In conclusion, this vulnerability highlights the importance of keeping your software up-to-date and being mindful of potential security issues in widely used open-source tools. Make sure to update your Binutils package, and stay informed about the latest security vulnerabilities affecting the software you rely on. Stay safe and happy coding!

Timeline

Published on: 08/22/2023 19:16:00 UTC
Last modified on: 08/26/2023 02:14:00 UTC