CVE-2019-0191 in Karaf
Summary
by MITRE
Apache Karaf kar deployer reads .kar archives and extracts the paths from the "repository/" and "resources/" entries in the zip file. It then writes out the content of these paths to the Karaf repo and resources directories. However, it doesn't do any validation on the paths in the zip file. This means that a malicious user could craft a .kar file with ".." directory names and break out of the directories to write arbitrary content to the filesystem. This is the "Zip-slip" vulnerability - https://snyk.io/research/zip-slip-vulnerability. This vulnerability is low if the Karaf process user has limited permission on the filesystem. Any Apache Karaf releases prior 4.2.3 is impacted.
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Analysis
by VulDB Data Team • 08/03/2023
The vulnerability identified as CVE-2019-0191 represents a critical directory traversal flaw within Apache Karaf's kar deployer component that falls under the well-documented Zip-slip vulnerability category. This security weakness stems from insufficient input validation during the extraction process of .kar archive files, which are commonly used for deploying applications and configurations within the Apache Karaf container environment. The flaw specifically manifests when the deployer processes zip archives containing paths that include directory traversal sequences such as ".." that allow attackers to escape the intended target directories and write files to arbitrary locations on the filesystem. The vulnerability is particularly dangerous because it leverages the standard zip file extraction mechanism without implementing proper path sanitization checks, making it a prime example of improper input validation that directly maps to CWE-22 - Improper Limitation of a Pathname to a Restricted Directory. The attack vector involves crafting a malicious .kar file that contains specially formatted paths in the repository/ and resources/ entries, enabling an attacker to bypass the intended security boundaries of the Karaf deployment environment.
The operational impact of this vulnerability extends far beyond simple file system manipulation, as it provides attackers with the capability to potentially compromise the entire Karaf runtime environment and underlying system. When exploited, the vulnerability allows for arbitrary file creation, modification, or deletion outside of the designated deployment directories, potentially leading to privilege escalation, code execution, or complete system compromise depending on the permissions of the Karaf process user. The severity of this vulnerability is particularly concerning in production environments where Karaf might run with elevated privileges, as it could enable attackers to install backdoors, modify critical system files, or corrupt the application deployment infrastructure. The low severity classification mentioned in the original description only applies when the Karaf process operates with limited filesystem permissions, but in typical enterprise deployments where service accounts have broader access rights, this vulnerability becomes a significant threat vector. This aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: PowerShell, as attackers could leverage this vulnerability to establish persistent access through malicious file placement. The vulnerability affects all Apache Karaf versions prior to 4.2.3, indicating that a substantial portion of deployments would have been exposed to this risk for an extended period.
Mitigation strategies for CVE-2019-0191 must address both immediate remediation and long-term architectural security improvements to prevent similar vulnerabilities from occurring in the future. The primary and most effective mitigation is upgrading to Apache Karaf version 4.2.3 or later, which includes the necessary path validation fixes that prevent directory traversal during zip extraction operations. Organizations should also implement strict file validation policies for all deployment artifacts, particularly those that involve automatic extraction processes. Additional protective measures include running the Karaf process with minimal required privileges, implementing proper file system access controls, and deploying monitoring solutions to detect unauthorized file system modifications. Security teams should conduct comprehensive vulnerability assessments to identify any other components within their deployment environment that might be susceptible to similar Zip-slip vulnerabilities, as this type of flaw is not unique to Apache Karaf but appears across many software systems that process untrusted archive files. The remediation process should also include establishing secure deployment practices that validate the integrity of all .kar files before deployment, potentially through cryptographic signatures or checksum verification mechanisms. Furthermore, implementing network segmentation and access controls around Karaf deployment environments can limit the potential impact of successful exploitation attempts. This vulnerability highlights the importance of following secure coding practices and implementing proper input validation at all levels of software architecture, particularly when handling untrusted data from external sources, as outlined in security standards such as OWASP Top 10 and NIST SP 800-160.