CVE-2017-9274 in obs-service-source_validator
Summary
by MITRE
A shell command injection in the obs-service-source_validator before 0.7 could be used to execute code as the packager when checking RPM SPEC files with specific macro constructs.
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Analysis
by VulDB Data Team • 02/16/2023
The vulnerability identified as CVE-2017-9274 represents a critical shell command injection flaw within the obs-service-source_validator tool, which operates as part of the Open Build Service ecosystem. This tool is designed to validate source packages and RPM spec files, serving as an essential component in the software packaging and distribution process for various Linux distributions. The vulnerability specifically affects versions prior to 0.7 of the source validator service, creating a significant security risk when processing RPM spec files that contain particular macro constructs. The flaw arises from insufficient input sanitization and improper handling of user-provided data within the validation process, potentially allowing malicious actors to inject arbitrary shell commands.
The technical implementation of this vulnerability stems from the service's failure to properly escape or sanitize macro variables within RPM spec files during the validation phase. When the obs-service-source_validator encounters specific macro constructs, it directly incorporates these elements into shell commands without adequate sanitization measures. This creates a classic command injection scenario where attacker-controlled input can be executed with the privileges of the packager account. The vulnerability is particularly dangerous because it operates within a trusted validation context, meaning that legitimate packaging workflows could be exploited to execute arbitrary code. This weakness aligns with CWE-78, which specifically addresses improper neutralization of special elements used in OS commands, and represents a direct violation of secure coding practices for command execution.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to escalate privileges within the packaging environment. When an attacker can inject commands that execute with packager privileges, they gain access to the build system's resources and potentially to sensitive information or infrastructure. The attack vector requires that the malicious actor has access to create or modify RPM spec files that will be processed by the vulnerable validator, which could occur through various means including supply chain attacks, compromised build environments, or social engineering targeting developers. This vulnerability affects the integrity and confidentiality of the software packaging pipeline, potentially leading to unauthorized code deployment, data exfiltration, or further compromise of the build infrastructure.
Mitigation strategies for CVE-2017-9274 should focus on immediate version updates to obs-service-source_validator 0.7 or later, which contain the necessary patches to address the command injection flaw. Organizations should also implement additional defensive measures including input validation at multiple layers, privilege separation for packaging operations, and monitoring of unusual command execution patterns. The fix typically involves proper escaping or sanitization of macro variables before they are incorporated into shell commands, ensuring that special characters and command delimiters are properly handled. Security teams should also consider implementing runtime protections such as sandboxing or containerization of packaging processes to limit the potential impact of any remaining vulnerabilities. This remediation approach aligns with ATT&CK technique T1059.001 for command and scripting interpreter, emphasizing the importance of preventing command injection attacks through proper input handling and privilege management. Organizations should also conduct thorough security assessments of their build environments to identify any other potential command injection vulnerabilities that could be exploited in similar contexts.