CVE-2021-21317 : Vulnerability Insights and Analysis
Learn about CVE-2021-21317, a medium-severity vulnerability in uap-core npm package. Understand the impact, affected versions, exploitation, and mitigation steps.
Understanding CVE-2021-21317
This CVE involves a vulnerability in uap-core, which is an open-source npm package for parsing user agent strings. The vulnerability exists in versions prior to 0.11.0, allowing remote attackers to perform a denial-of-service attack through maliciously crafted long strings.
What is CVE-2021-21317?
uap-core, a crucial component in user agent string parsing, is susceptible to regular expression denial of service (REDoS) due to overlapping capture groups. This flaw enables attackers to overload servers by exploiting the User-Agent header in HTTP(S) requests.
The Impact of CVE-2021-21317
The impact of this CVE is rated as MEDIUM with a CVSS base score of 5.3. Although the confidentiality, integrity, and privileges are not affected, the attack vector is through the network, potentially causing a denial of service.
Technical Details of CVE-2021-21317
In-depth technical details of the vulnerability, affected systems, and exploitation mechanisms.
Vulnerability Description
The vulnerability arises from overlapping capture groups in uap-core's regexes, leading to a potential denial-of-service attack via crafted User-Agent headers in HTTP(S) requests.
Affected Systems and Versions
Versions of uap-core up to 0.11.0 are impacted by this vulnerability, putting systems relying on these versions at risk of a denial-of-service attack.
Exploitation Mechanism
Exploiting this CVE involves sending specially crafted long strings in the User-Agent header of HTTP(S) requests to overwhelm the server, resulting in a denial-of-service condition.
Mitigation and Prevention
Actions to mitigate and prevent exploitation of CVE-2021-21317.
Immediate Steps to Take
Users are advised to update uap-core to version 0.11.0 or later to patch the vulnerability and protect the server from potential denial-of-service attacks.
Long-Term Security Practices
Employing secure coding practices, regularly updating software dependencies, and monitoring for any anomalies in User-Agent headers can help prevent future attacks.
Patching and Updates
Continuously monitor for security advisories and update uap-core and dependent packages to the latest secure versions to avoid exposure to known vulnerabilities.