CVE-2016-15011 in dssp
Summary
by MITRE • 01/09/2023
A vulnerability classified as problematic was found in e-Contract dssp up to 1.3.1. Affected by this vulnerability is the function checkSignResponse of the file dssp-client/src/main/java/be/e_contract/dssp/client/SignResponseVerifier.java. The manipulation leads to xml external entity reference. Upgrading to version 1.3.2 is able to address this issue. The name of the patch is ec4238349691ec66dd30b416ec6eaab02d722302. It is recommended to upgrade the affected component. The identifier VDB-217549 was assigned to this vulnerability.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/29/2023
The vulnerability identified as CVE-2016-15011 represents a critical xml external entity reference flaw within the e-Contract dssp software version 1.3.1 and earlier. This vulnerability specifically resides in the checkSignResponse function located within the dssp-client/src/main/java/be/e_contract/dssp/client/SignResponseVerifier.java file, making it a targeted weakness in the digital signature verification process. The flaw enables malicious actors to manipulate xml input streams and potentially trigger unauthorized external entity references during the signature verification workflow, creating a potential attack vector that could compromise the integrity and security of digital signature operations.
The technical implementation of this vulnerability stems from inadequate xml parsing controls within the SignResponseVerifier component, which fails to properly sanitize or restrict external entity references in xml documents. This weakness allows attackers to craft malicious xml payloads that can reference external resources, potentially leading to information disclosure, denial of service attacks, or even remote code execution depending on the underlying xml parser configuration. The vulnerability operates at the application layer and specifically affects systems that process digital signatures through the e-Contract dssp client library, making it particularly dangerous in environments where digital signature validation is critical for security operations. This flaw directly maps to CWE-611, which categorizes xml external entity processing vulnerabilities, and aligns with ATT&CK technique T1210 for exploitation of weaknesses in xml parsers.
The operational impact of this vulnerability extends beyond simple data exposure, as it fundamentally compromises the trust model of digital signature verification systems. Organizations relying on e-Contract dssp for signature validation may unknowingly process malicious xml documents that could redirect signature verification to unauthorized endpoints or extract sensitive information from internal systems. The vulnerability affects not just the immediate signature verification process but could potentially enable broader attacks against the underlying infrastructure that processes these digital signatures, particularly in enterprise environments where digital signatures are used for document authentication and secure communications. Security teams must consider this vulnerability as part of their broader threat landscape, as it could be leveraged in conjunction with other attacks targeting the same vulnerable components.
The recommended mitigation strategy involves upgrading the affected e-Contract dssp component to version 1.3.2, which incorporates the patch identified by the commit hash ec4238349691ec66dd30b416ec6eaab02d722302. This upgrade addresses the root cause by implementing proper xml entity validation and restriction mechanisms within the SignResponseVerifier class. Organizations should also consider implementing additional security controls such as xml input validation, network segmentation, and monitoring for suspicious xml parsing activities. The patch resolution specifically targets the vulnerable function by ensuring that external entity references are properly handled and restricted, preventing attackers from manipulating the xml parsing process to achieve unauthorized access or information disclosure. Security professionals should verify that the upgrade has been properly implemented and test the system to ensure that the vulnerability has been fully remediated without introducing regressions in functionality.