CVE-2020-11729 in Andrew's Web Libraries
Summary
by MITRE
An issue was discovered in DAViCal Andrew's Web Libraries (AWL) through 0.60. Long-term session cookies, uses to provide long-term session continuity, are not generated securely, enabling a brute-force attack that may be successful.
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Analysis
by VulDB Data Team • 05/27/2024
The vulnerability CVE-2020-11729 affects DAViCal Andrew's Web Libraries version 0.60 and earlier, representing a significant security weakness in session management implementation. This flaw specifically targets the generation of long-term session cookies that are designed to maintain user sessions across extended periods, typically providing convenience for users who need persistent access to calendar and scheduling services. The issue arises from inadequate cryptographic randomness in the cookie generation process, creating predictable session identifiers that can be systematically guessed or computed through brute-force techniques.
The technical implementation flaw stems from the use of insufficiently random or predictable methods for generating session tokens within the AWL framework. When long-term session cookies are created, they should utilize cryptographically secure random number generators to ensure uniqueness and unpredictability. However, in this vulnerable version, the implementation fails to meet these security requirements, resulting in session identifiers that exhibit patterns or low entropy characteristics. This weakness directly violates established security principles for session management and authentication mechanisms, making the system susceptible to automated attack vectors that can systematically test potential session values.
From an operational perspective, this vulnerability presents a substantial risk to organizations relying on DAViCal for calendar and scheduling services, particularly those handling sensitive or confidential data. Attackers can leverage brute-force techniques to discover valid session cookies, potentially gaining unauthorized access to user accounts and calendar data without proper authentication. The impact extends beyond simple unauthorized access as compromised sessions can lead to data modification, deletion, or exposure of private scheduling information. The vulnerability is particularly concerning because it affects long-term sessions, meaning that successful exploitation could provide extended unauthorized access periods, making detection more difficult and increasing the potential damage.
The security implications of this vulnerability align with CWE-330, which addresses the use of insecure random number generators in security contexts. This weakness creates opportunities for attackers to perform session hijacking attacks, which are categorized under the ATT&CK framework as T1566.001 - Phishing and T1566.002 - Spearphishing Attachment, as compromised sessions can be used to establish persistent access. Organizations using affected versions should implement immediate mitigations including updating to patched versions of DAViCal, implementing additional authentication layers, and monitoring for suspicious session activity. The vulnerability also highlights the importance of proper session management practices and adherence to security standards such as those outlined in NIST SP 800-63B for digital identity management and authentication protocols.