CVE-2021-37634 : Exploit Details and Defense Strategies
Learn about CVE-2021-37634, a vulnerability in LeafKit that allows XSS attacks with untrusted user input. Find out the impact, technical details, and mitigation steps.
LeafKit allows XSS with untrusted user input.
Understanding CVE-2021-37634
LeafKit, a templating language with Swift-inspired syntax, is vulnerable to Cross-site Scripting (XSS) attacks.
What is CVE-2021-37634?
Versions of LeafKit prior to 1.3.0 are susceptible to XSS attacks when passing unsanitized data to Leaf's variable tags. Attackers can inject scripts into generated pages, enabling XSS attacks without proper mitigation.
The Impact of CVE-2021-37634
The vulnerability has a CVSS base score of 7.4 (High severity) and can lead to high confidentiality impact. It requires user interaction and network access to exploit.
Technical Details of CVE-2021-37634
LeafKit before version 1.3.0 allows XSS due to inadequate data sanitization.
Vulnerability Description
Attackers passing unsanitized data to Leaf's variable tags can inject scripts into generated web pages, enabling XSS attacks.
Affected Systems and Versions
LeafKit versions prior to 1.3.0 are impacted by this vulnerability.
Exploitation Mechanism
Attackers exploit this vulnerability by injecting malicious scripts into web pages through unsanitized data passed to Leaf's variable tags.
Mitigation and Prevention
To mitigate the CVE-2021-37634 vulnerability:
Immediate Steps to Take
- Update LeafKit to version 1.3.0 or newer
- Sanitize untrusted input before passing it to Leaf
- Enable a Content Security Policy (CSP) to block inline script and CSS data
Long-Term Security Practices
- Regularly update software components
- Educate developers on secure coding practices
Patching and Updates
Ensure timely patching of LeafKit to the latest version to address the XSS vulnerability.