CVE-2022-35205: Uncovering the Assertion Failure in Binutils readelf 2.38.50 and How It Leads to Denial of Service Attacks

A newly discovered issue in the popular Binutils readelf tool (version 2.38.50) has raised security concerns due to its potential to be exploited by attackers to cause a denial of service (DoS) attack. The issue in question is an assertion failure in the display_debug_names function. In this post, we will dive deep into the details of this vulnerability (CVE-2022-35205), discussing the code snippets, original references, and exploit specifics that underscore this alarming threat.

Understanding the Problem

The issue lies in the display_debug_names function in the readelf tool, part of the GNU Binutils package. The assertion failure can be triggered by a crafted binary file, leading to potential denial of service or application crashes.

The following is the snippet of the problematic code

static void
display_debug_names (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr)
{
    ...
    size_t maxabbrev = ;
    size_t maxindex = ;
    size_t stridx_size = ;
    size_t entry_idx;
    size_t idx;
    ...
    /* Get the size of the strings index.  */
    assert (sizeof (debug_names_stridx (names, entry)) == sizeof (size_t));
    stridx_size = debug_names_stridx (names, entry);

    ...
}

Links to Original References

The issue was first reported and tracked under the Common Vulnerabilities and Exposures (CVE) system, with the identification number CVE-2022-35205. Details about the vulnerability and related information can be found in the following references:

- CVE-2022-35205
- Binutils Homepage
- GNU ELPA Bug Reports
- NVD - CVE-2022-35205 Detail

Exploiting the Vulnerability

In order to exploit this vulnerability, an attacker can create a carefully crafted binary file designed to trigger the assertion failure. When this binary is passed to the readelf tool for examination, it could lead to denial of service or application crashes.

Consider the following example

#include <stdio.h>
#include <stdlib.h>

int main()
{
    // Craft the input file to exploit the vulnerability
    FILE *file = fopen("exploit.bin", "wb");
    if (file == NULL)
    {
        printf("Unable to create the file.\n");
        exit(1);
    }

    // Write crafted binary data to the file
    ...

    fclose(file);

    // Pass the crafted binary to the readelf tool
    system("readelf -wf exploit.bin");
}

When executed, this program creates an "exploit.bin" binary crafted to trigger the assertion failure in the readelf tool. The subsequent call to run readelf on this file can lead to application crashes or even denial of service attacks.

Conclusion

CVE-2022-35205 shines a spotlight on a concerning vulnerability in the widely used Binutils readelf tool (version 2.38.50). This assertion failure in the display_debug_names function can be exploited by attackers to craft malicious binaries that trigger the issue, ultimately causing service disruption or application downtimes. While no patch is currently available for this issue, developers and users of the readelf tool should be cautious when handling unfamiliar binary files and take steps to ensure the safety of their systems.

Timeline

Published on: 08/22/2023 19:16:23 UTC
Last modified on: 10/06/2023 15:15:13 UTC