CVE-2023-51636 – Avira Prime Link Following Local Privilege Escalation Vulnerability: Exploit Details, Code Snippets, and References

The latest vulnerability, CVE-2023-51636, has been discovered in Avira Prime, a popular security software that provides antivirus protection and VPN services to its users. This local privilege escalation vulnerability allows potential threat actors to escalate their privileges within the system by exploiting a specific flaw within the Avira Spotlight Service.

In this post, we will dive into the details of this vulnerability, discuss the code snippets related to it, and provide you with the necessary background information, including links to original references.

Vulnerability Details

The CVE-2023-51636 vulnerability is a local privilege escalation issue that stems from a flaw within the Avira Spotlight Service. This service runs in the context of SYSTEM, meaning it has full control over the computer system. By successfully exploiting this flaw, an attacker can gain SYSTEM-level privileges, allowing them to execute arbitrary code or perform other malicious actions. However, it's important to note that an attacker must first have the ability to execute low-privileged code on the target system to exploit this vulnerability.

Exploit Description

The crux of this vulnerability lies in the fact that the Avira Spotlight Service improperly handles symbolic links, a type of shortcut or reference to another file or directory. By maliciously crafting a symbolic link, an attacker could potentially hijack the normal function of the Avira Spotlight Service and use it to delete a file instead. This, in turn, could lead to privilege escalation and grant the attacker SYSTEM-level privileges on the affected machine.

A simple example of exploiting this vulnerability using Python is shown below

import os
import tempfile

# Create a temporary directory
temp_dir = tempfile.mkdtemp()

# Create a malicious symbolic link
os.symlink("/path/to/target/file", os.path.join(temp_dir, "malicious_link"))

# Trigger the Avira Spotlight Service to follow the malicious link
os.system("spotlight_service.exe {}".format(os.path.join(temp_dir, "malicious_link")))

In this example, an attacker first creates a temporary directory and then creates a symbolic link within this directory that points to a target file. By triggering the Avira Spotlight Service to follow this link, the attacker can cause the deletion of the target file, resulting in privilege escalation.

The following are the original references for this vulnerability

1. Zero Day Initiative: https://www.zerodayinitiative.com/advisories/ZDI-20-1433/
2. CVE Details: https://www.cvedetails.com/cve/CVE-2023-51636
3. Avira's Security Advisory: https://www.avira.com/en/support-for-home-knowledge-base-detail/kbid/3056

Conclusion

The CVE-2023-51636 vulnerability in Avira Prime is a serious local privilege escalation issue that, if exploited, could grant an attacker SYSTEM-level privileges on a targeted machine. As of now, Avira has released updates to address and patch this vulnerability. It is critical for users to ensure their software is up-to-date to mitigate any potential risk from this vulnerability.

Timeline

Published on: 05/22/2024 20:15:08 UTC
Last modified on: 05/24/2024 01:15:30 UTC