CVE-2021-23336 Explained : Impact and Mitigation
Learn about CVE-2021-23336, a Python Web Cache Poisoning vulnerability affecting python/cpython versions before 3.6.13, its impact, technical details, and mitigation steps.
Web Cache Poisoning vulnerability in python/cpython versions before 3.6.13, 3.7.0 before 3.7.10, 3.8.0 before 3.8.8, 3.9.0 before 3.9.2 via urllib.parse.parse_qsl and parse_qs allows attackers to manipulate web caches.
Understanding CVE-2021-23336
This CVE identifies a Web Cache Poisoning vulnerability in python/cpython affecting several versions.
What is CVE-2021-23336?
The vulnerability enables attackers to exploit web cache mechanisms, leading to cache poisoning in urllib.parse functions.
The Impact of CVE-2021-23336
Attackers can manipulate web caches using semicolons to alter query parameters, potentially causing proxy-server misinterpretation and caching of malicious requests as safe ones.
Technical Details of CVE-2021-23336
The vulnerability in python/cpython stems from the improper handling of query parameters, allowing cache poisoning attacks.
Vulnerability Description
By using semicolons as separators in query parameters, attackers can deceive the proxy-server communication and poison web caches with malicious requests.
Affected Systems and Versions
The vulnerability impacts python/cpython versions 3.6.13, 3.7.10, 3.8.8, and 3.9.2 where urllib.parse functions are utilized.
Exploitation Mechanism
Exploiting the CVE involves manipulating query parameters using semicolons, triggering a discrepancy in how proxies and servers interpret requests, leading to cache poisoning.
Mitigation and Prevention
To safeguard systems from CVE-2021-23336, immediate steps should be taken along with long-term security practices and regular patching.
Immediate Steps to Take
Review and update affected python/cpython versions, implement additional security measures to prevent cache poisoning attacks.
Long-Term Security Practices
Adhere to secure coding practices, conduct regular security audits, and educate developers on secure coding to prevent future vulnerabilities.
Patching and Updates
Apply the latest patches provided by python/cpython to mitigate the Web Cache Poisoning vulnerability and enhance system security.