CVE-2020-21674 : Exploit Details and Defense Strategies

A heap-based buffer overflow vulnerability in libarchive-3.4.1dev can lead to a denial of service via a crafted archive file.

Understanding CVE-2020-21674

This CVE involves a specific function in libarchive that can be exploited by remote attackers to cause a crash through a buffer overflow.

What is CVE-2020-21674?

The vulnerability in archive_string_append_from_wcs() in libarchive-3.4.1dev allows attackers to trigger an out-of-bounds write in heap memory, resulting in a crash when processing a malicious archive file. Notably, this issue affects users who downloaded the development code from GitHub.

The Impact of CVE-2020-21674

The exploitation of this vulnerability can lead to a denial of service condition, causing the affected application to crash, potentially disrupting services or operations.

Technical Details of CVE-2020-21674

This section provides more in-depth technical insights into the vulnerability.

Vulnerability Description

The vulnerability arises from a heap-based buffer overflow in the archive_string_append_from_wcs() function within libarchive-3.4.1dev.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions: Only users who downloaded the development code of libarchive-3.4.1dev from GitHub are affected.

Exploitation Mechanism

Attackers can exploit this vulnerability by crafting a malicious archive file that triggers the out-of-bounds write in heap memory, leading to a crash.

Mitigation and Prevention

To address CVE-2020-21674, users and organizations should take immediate and long-term security measures.

Immediate Steps to Take

Avoid downloading or using the development code of libarchive-3.4.1dev from GitHub.
Implement network-level controls to filter out potentially malicious archive files.

Long-Term Security Practices

Regularly update software and libraries to patched versions.
Conduct security assessments and code reviews to identify and mitigate similar vulnerabilities.

Patching and Updates

Stay informed about security advisories and updates from libarchive.
Apply patches or updates provided by the vendor to address the vulnerability.