CVE-2022-3560 in pesign
Summary
by MITRE • 02/02/2023
A flaw was found in pesign. The pesign package provides a systemd service used to start the pesign daemon. This service unit runs a script to set ACLs for /etc/pki/pesign and /run/pesign directories to grant access privileges to users in the 'pesign' group. However, the script doesn't check for symbolic links. This could allow an attacker to gain access to privileged files and directories via a path traversal attack.
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Analysis
by VulDB Data Team • 03/04/2023
The vulnerability identified as CVE-2022-3560 resides within the pesign package, a security tool designed to manage digital signatures and certificate handling in Linux environments. This flaw specifically affects the systemd service component that initializes the pesign daemon, creating a critical security gap that could be exploited by malicious actors to bypass intended access controls. The pesign package operates by establishing a daemon service that requires specific directory permissions to function correctly, with the service unit responsible for configuring access controls through a dedicated script. The implementation of this access control mechanism involves setting up access control lists for the /etc/pki/pesign and /run/pesign directories, which are essential for maintaining the security boundaries of the signing operations.
The technical flaw manifests in the script's failure to properly validate symbolic links during the access control configuration process. This oversight creates a path traversal vulnerability that allows attackers to manipulate the directory structure in ways that were not anticipated during the design phase. When the script processes the directory setup, it does not verify whether the target paths are symbolic links, which means that an attacker could potentially create malicious symbolic links that point to privileged directories outside the intended scope. This weakness aligns with CWE-22, which specifically addresses path traversal vulnerabilities where insufficient input validation allows attackers to access files and directories outside the intended scope. The vulnerability represents a classic case of inadequate path validation that could be exploited through a combination of symbolic link manipulation and privilege escalation techniques.
The operational impact of this vulnerability extends beyond simple access control bypass, as it could potentially allow attackers to gain unauthorized access to sensitive certificate files, private keys, and other security-critical components stored within the pesign directory structure. An attacker exploiting this vulnerability could manipulate the access control lists to grant themselves privileges that should be restricted to the pesign group, thereby undermining the security model of the entire signing infrastructure. This risk is particularly concerning because pesign is typically used in environments where digital signatures and certificate management are critical components of security operations, making the compromise of such systems potentially devastating for organizations relying on these tools for code signing, package verification, or other cryptographic operations. The vulnerability could enable attackers to perform unauthorized certificate operations or access sensitive cryptographic material that could be used for further attacks within the compromised environment.
Mitigation strategies for CVE-2022-3560 should focus on immediate remediation through patch updates provided by the maintainers of the pesign package, as well as implementing additional operational controls to monitor and validate directory structures. Organizations should ensure that all symbolic links within the pesign directory hierarchy are properly validated and that any access control changes are subject to thorough audit procedures. The implementation of proper input validation and path resolution checks should be enforced in the service script to prevent the exploitation of symbolic link vulnerabilities. Security teams should also consider implementing monitoring solutions that can detect unauthorized modifications to directory structures or access control list changes that might indicate an attempted exploitation of this vulnerability. This remediation approach aligns with ATT&CK technique T1068, which covers the exploitation of legitimate credentials and system access controls, and reflects the importance of maintaining proper privilege separation and access control mechanisms in security-critical applications. The vulnerability demonstrates the critical importance of comprehensive input validation and path resolution in security-sensitive software components, particularly those that handle privileged operations and access control management.