CVE-2020-11037 in Wagtail
Summary
by MITRE
In Wagtail before versions 2.7.2 and 2.8.2, a potential timing attack exists on pages or documents that have been protected with a shared password through Wagtail's "Privacy" controls. This password check is performed through a character-by-character string comparison, and so an attacker who is able to measure the time taken by this check to a high degree of accuracy could potentially use timing differences to gain knowledge of the password. This is understood to be feasible on a local network, but not on the public internet. Privacy settings that restrict access to pages/documents on a per-user or per-group basis (as opposed to a shared password) are unaffected by this vulnerability. This has been patched in 2.7.3, 2.8.2, 2.9.
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Analysis
by VulDB Data Team • 11/19/2024
This vulnerability exists within the Wagtail content management system where the privacy controls for protecting pages or documents with shared passwords are susceptible to timing attacks. The flaw stems from the implementation of character-by-character string comparison during password verification, which creates measurable time differences that can be exploited by attackers with sufficient precision in timing measurements. The vulnerability specifically affects versions prior to 2.7.2 and 2.8.2, where the password validation mechanism does not employ constant-time string comparison techniques that would obscure timing variations inherent in the verification process.
The technical implementation of this vulnerability aligns with CWE-203, which addresses the exposure of sensitive information through timing differences, and represents a classic example of a timing side-channel attack. When a user enters a password for access to restricted content, the system performs a sequential character-by-character comparison between the entered password and the stored hash. Each character comparison takes measurable time, and attackers can exploit these timing variations to infer information about the correct password. The attack is most effective within local network environments where network latency variations are minimal and precise timing measurements can be achieved through tools like network sniffers or specialized timing measurement software.
The operational impact of this vulnerability extends beyond simple password guessing, as it provides attackers with a methodical approach to password recovery through statistical analysis of timing data. Even if the password is complex, an attacker with sufficient computational resources and network proximity can systematically determine each character of the password by measuring response times for different character inputs. This attack vector is particularly concerning because it operates at the application level without requiring authentication or exploitation of other system vulnerabilities, making it a stealthy method for unauthorized access to protected content. The vulnerability affects only shared password protections and does not impact user or group-based access controls, which maintain proper security mechanisms.
Mitigation strategies for this vulnerability include implementing constant-time string comparison algorithms that ensure identical processing time regardless of input differences, which directly addresses the timing side-channel weakness. The patched versions 2.7.3, 2.8.2, and 2.9 incorporate proper cryptographic timing mechanisms that prevent attackers from gaining information through timing variations. Organizations should also consider implementing additional security controls such as rate limiting for authentication attempts, monitoring for unusual access patterns, and ensuring that password policies enforce sufficiently complex passwords to make brute force attacks impractical. The ATT&CK framework categorizes this as a credential access technique through timing attacks, and the remediation aligns with defensive measures against information disclosure vulnerabilities. Network segmentation and access controls should be implemented to limit the attack surface, particularly for systems where local network access is possible, as this vulnerability is specifically noted to be feasible within local network environments.