CVE-2020-11108 : Security Advisory and Response
Learn about CVE-2020-11108, a critical vulnerability in Pi-hole through 4.4 allowing remote code execution and privilege escalation. Find mitigation steps and best practices here.
Pi-hole through 4.4 allows an authenticated adversary to upload arbitrary files, leading to Remote Code Execution and potential privilege escalation.
Understanding CVE-2020-11108
The Gravity updater in Pi-hole through version 4.4 is vulnerable to a critical security issue that enables an attacker to execute arbitrary code.
What is CVE-2020-11108?
The vulnerability in the Gravity updater of Pi-hole allows an authenticated attacker to upload any files, potentially leading to Remote Code Execution by manipulating PHP files in the web directory. Additionally, it can be exploited in combination with the sudo rule for the www-data user to escalate privileges to root.
The Impact of CVE-2020-11108
This vulnerability poses a severe risk as it allows attackers to execute malicious code on the affected system, potentially leading to complete compromise of the Pi-hole instance and the underlying system.
Technical Details of CVE-2020-11108
The technical aspects of the CVE-2020-11108 vulnerability provide insight into its nature and potential risks.
Vulnerability Description
The flaw resides in the gravity_DownloadBlocklistFromUrl function in gravity.sh, enabling an authenticated adversary to upload arbitrary files, which can be leveraged for Remote Code Execution.
Affected Systems and Versions
- Pi-hole versions up to 4.4 are impacted by this vulnerability.
Exploitation Mechanism
- Attackers can exploit this vulnerability by uploading malicious files through the Gravity updater, allowing them to execute arbitrary code on the target system.
Mitigation and Prevention
Protecting systems from CVE-2020-11108 requires immediate actions and long-term security measures.
Immediate Steps to Take
- Update Pi-hole to the latest version to patch the vulnerability.
- Monitor system logs for any suspicious activities or file uploads.
- Restrict access to the Pi-hole web directory to authorized users only.
Long-Term Security Practices
- Implement strong authentication mechanisms to prevent unauthorized access.
- Regularly audit and review system configurations and permissions.
Patching and Updates
- Apply security patches promptly to ensure that known vulnerabilities are mitigated effectively.