CVE-2018-12356 in Simple Password Store
Summary
by MITRE
An issue was discovered in password-store.sh in pass in Simple Password Store 1.7.x before 1.7.2. The signature verification routine parses the output of GnuPG with an incomplete regular expression, which allows remote attackers to spoof file signatures on configuration files and extension scripts. Modifying the configuration file allows the attacker to inject additional encryption keys under their control, thereby disclosing passwords to the attacker. Modifying the extension scripts allows the attacker arbitrary code execution.
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Analysis
by VulDB Data Team • 03/27/2023
The vulnerability identified as CVE-2018-12356 resides within the password-store.sh component of the Simple Password Store utility, specifically affecting versions 1.7.x prior to 1.7.2. This flaw represents a critical security weakness that undermines the integrity verification mechanisms designed to protect password storage systems. The issue stems from an insufficient regular expression implementation within the signature verification routine that processes GnuPG output, creating a pathway for malicious actors to exploit the system's trust model.
The technical implementation flaw manifests through an incomplete regular expression pattern that fails to properly validate GnuPG signature outputs during verification processes. This parsing error enables attackers to craft malicious signatures that appear legitimate to the verification routine, thereby bypassing the cryptographic integrity checks that should prevent unauthorized modifications. The vulnerability operates at the intersection of input validation and cryptographic verification, where the insufficient regex pattern creates a false positive condition that accepts forged signatures as authentic.
Attackers exploiting this vulnerability can achieve multiple levels of compromise within the password store system. The primary attack vector involves modifying configuration files to inject additional encryption keys controlled by the adversary, which directly results in unauthorized access to stored passwords. This configuration manipulation represents a privilege escalation attack that fundamentally compromises the security model of the password store. Additionally, attackers can modify extension scripts to achieve arbitrary code execution, transforming this vulnerability into a full system compromise capability that can be leveraged for further infiltration.
The operational impact of CVE-2018-12356 extends beyond simple credential theft to encompass complete system compromise potential. Organizations relying on Simple Password Store for credential management face significant risk exposure, as attackers can gain access to sensitive password data while simultaneously establishing persistent execution capabilities. This vulnerability directly violates security principles outlined in the Common Weakness Enumeration catalog under CWE-20, which addresses "Improper Input Validation" and CWE-347, "Improper Verification of Cryptographic Signature," demonstrating the dual nature of the flaw.
The attack surface for this vulnerability aligns with several MITRE ATT&CK framework techniques, particularly those related to privilege escalation and execution through modification of system components. The ability to inject encryption keys maps to ATT&CK technique T1059, "Command and Scripting Interpreter," while the arbitrary code execution capability corresponds to T1068, "Local Port Forwarding." The configuration file manipulation represents a form of persistence establishment under T1078, "Valid Accounts," as attackers can maintain control over the compromised system through the injected keys.
Organizations should implement immediate mitigation strategies including updating to Simple Password Store version 1.7.2 or later, which contains the corrected signature verification routine. Additionally, security teams should conduct comprehensive audits of all password store configurations to identify potential compromise indicators and implement monitoring for unauthorized configuration changes. The vulnerability demonstrates the critical importance of proper input validation in cryptographic systems and serves as a reminder of the potential consequences when regular expression patterns fail to adequately validate security-critical outputs from cryptographic tools.