CVE-2022-1379 in plantuml
Summary
by MITRE • 05/14/2022
URL Restriction Bypass in GitHub repository plantuml/plantuml prior to V1.2022.5. An attacker can abuse this to bypass URL restrictions that are imposed by the different security profiles and achieve server side request forgery (SSRF). This allows accessing restricted internal resources/servers or sending requests to third party servers.
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Analysis
by VulDB Data Team • 05/18/2022
The vulnerability identified as CVE-2022-1379 represents a critical security flaw in the PlantUML repository management system prior to version 1.2022.5. This issue manifests as a URL restriction bypass mechanism that undermines the intended security controls designed to prevent unauthorized access to internal network resources. The vulnerability specifically affects the URL validation and filtering mechanisms that are essential for protecting against server-side request forgery attacks. PlantUML, a popular tool for generating diagrams from textual descriptions, implements various security profiles to restrict external resource access during diagram generation processes. These security measures are crucial for preventing attackers from leveraging the diagram generation functionality to access internal systems or exfiltrate data.
The technical implementation of this vulnerability stems from insufficient input validation and URL parsing logic within the PlantUML processing pipeline. When the system encounters certain malformed or specially crafted URLs, it fails to properly validate the resource requests against the configured security restrictions. This allows attackers to craft requests that appear to comply with security policies while actually bypassing these controls through subtle manipulation of URL formats or encoding techniques. The flaw enables attackers to construct requests that traverse the intended security boundaries, effectively circumventing the protection mechanisms that should prevent access to internal resources or external servers. This bypass occurs at the URL parsing layer where the system does not adequately sanitize or validate the URLs before processing them.
The operational impact of this vulnerability is significant as it provides attackers with the capability to perform server-side request forgery attacks against systems running vulnerable versions of PlantUML. An attacker could potentially access internal network resources that should remain protected from external access, including internal APIs, databases, or administrative interfaces. Additionally, the vulnerability allows for requests to be sent to third-party servers, potentially enabling data exfiltration or the exploitation of other systems through the PlantUML service. This creates a substantial risk for organizations that use PlantUML for diagram generation in environments where internal network security is paramount, as the vulnerability can be exploited to gain unauthorized access to sensitive resources without proper authentication or authorization.
The vulnerability aligns with CWE-1236, which addresses the bypass of security restrictions, and demonstrates characteristics consistent with the ATT&CK technique T1071.004 for application layer protocol traffic. Organizations using PlantUML should immediately upgrade to version 1.2022.5 or later to address this vulnerability. Mitigation strategies include implementing network-level restrictions, deploying web application firewalls, and ensuring that all external dependencies are properly validated. Security monitoring should be enhanced to detect unusual patterns in URL requests that might indicate exploitation attempts. Additionally, organizations should conduct thorough security assessments of their PlantUML implementations and review access controls to minimize potential impact if the vulnerability is exploited in environments where the service is exposed to untrusted networks. The fix implemented in version 1.2022.5 addresses the core URL validation logic to properly enforce security restrictions and prevent the bypass mechanism that allowed unauthorized access to internal resources.