CVE-2019-10136 in Spacewalk
Summary
by MITRE
It was found that Spacewalk, all versions through 2.8, did not safely compute client token checksums. An attacker with a valid, but expired, authenticated set of headers could move some digits around, artificially extending the session validity without modifying the checksum.
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Analysis
by VulDB Data Team • 10/15/2023
The vulnerability identified as CVE-2019-10136 affects Spacewalk server software versions through 2.8, representing a critical session management flaw that undermines the authentication security model. This issue stems from improper handling of client token checksums within the system's authentication framework, creating a persistent security weakness that allows attackers to manipulate session validity periods.
The technical flaw manifests in the insufficient cryptographic validation of authentication headers within Spacewalk's session management system. When a client presents valid authentication credentials that have subsequently expired, the system fails to properly validate the checksum calculations associated with these headers. This vulnerability enables attackers to modify specific digits within the authentication token structure while maintaining the overall checksum validity, thereby artificially extending session lifetimes without requiring additional authentication credentials. The flaw essentially creates a path for session hijacking through simple manipulation of header values.
From an operational perspective, this vulnerability presents significant risks to system security and integrity. An attacker who gains access to a valid but expired authentication session can extend their access period indefinitely by making minimal modifications to the token structure. This allows for extended unauthorized access to system resources, potentially enabling data exfiltration, system manipulation, or further reconnaissance activities. The impact extends beyond simple unauthorized access as it undermines the fundamental security assumptions of the authentication system, making it difficult to detect and trace malicious activities.
The vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in checksum or hash computation, and relates to ATT&CK technique T1550.001 for legitimate credentials and T1550.003 for additional access through session hijacking. Organizations using Spacewalk versions through 2.8 face potential compromise of their entire system security posture, as this vulnerability can be exploited without requiring sophisticated attack techniques or additional privileges. The remediation approach requires immediate patching of the Spacewalk software to implement proper checksum validation mechanisms and potentially implementing additional session monitoring and enforcement measures to detect anomalous session behavior patterns.
This vulnerability demonstrates the critical importance of proper cryptographic implementation in authentication systems, as weak checksum validation can create persistent backdoors for attackers. The flaw represents a design-level issue rather than a simple coding error, requiring comprehensive system reevaluation and potentially architectural changes to ensure robust session management. Organizations should implement immediate monitoring for suspicious session activity and consider implementing additional authentication layers or more robust session validation mechanisms until the official patches are deployed across all affected systems.