CVE-2013-6956 in IVE OS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Secure Access Service Web rewriting feature in Juniper Junos Pulse Secure Access Service (aka SSL VPN) with IVE OS before 7.1r17, 7.3 before 7.3r8, 7.4 before 7.4r6, and 8.0 before 8.0r1, when web rewrite is enabled, allows remote authenticated users to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 06/04/2021
The CVE-2013-6956 vulnerability represents a critical cross-site scripting flaw within Juniper Junos Pulse Secure Access Service, specifically affecting the Secure Access Service Web rewriting feature. This vulnerability exists in the IVE OS version prior to the specified patches, impacting multiple release branches including 7.1r17, 7.3r8, 7.4r6, and 8.0r1. The flaw resides in how the system processes web rewriting functionality, creating a pathway for malicious actors to execute unauthorized code within the context of affected user sessions. This vulnerability specifically affects environments where web rewriting is enabled, making it particularly dangerous for organizations relying on this feature for secure remote access services.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding within the web rewriting module of the Junos Pulse Secure Access Service. When web rewriting is enabled, the system processes user-supplied input through the Secure Access Service interface without adequate sanitization mechanisms. This allows authenticated attackers to inject malicious script code or HTML elements that persist within the application's response handling. The vulnerability's classification aligns with CWE-79, which specifically addresses cross-site scripting flaws where improper validation of input data leads to execution of malicious scripts in the victim's browser context. The attack vector leverages the legitimate authentication process, making it particularly insidious as it operates within the bounds of normal user privileges.
The operational impact of CVE-2013-6956 extends beyond simple script injection, potentially enabling attackers to escalate privileges and access sensitive data within the secure access environment. An authenticated user can exploit this vulnerability to craft malicious web requests that, when processed by the affected system, execute arbitrary code in the browser of other users. This capability allows for session hijacking, credential theft, and data exfiltration from within the secure network perimeter. The vulnerability's presence in multiple versions of the IVE OS indicates a systemic flaw in the input sanitization process, affecting organizations with legacy deployments. The attack requires only authentication access to the system, making it particularly dangerous in environments where users may have elevated privileges or where the system serves as a gateway to sensitive corporate resources. This vulnerability directly maps to ATT&CK technique T1059.007 for scripting languages, specifically targeting web-based scripting environments where user input is improperly handled.
Organizations affected by CVE-2013-6956 should implement immediate mitigations including applying the vendor-provided patches for each affected version branch, disabling web rewriting functionality where possible, and implementing additional network-level controls such as web application firewalls. The remediation process requires careful version management to ensure all affected systems receive appropriate patches, as the vulnerability spans multiple major releases and service packs. Network segmentation and monitoring should be enhanced to detect potential exploitation attempts, particularly around authentication and web rewriting functions. Security teams should also consider implementing input validation controls at multiple layers, including application-level filtering and content security policies. The vulnerability demonstrates the importance of maintaining current security patches and highlights the need for regular vulnerability assessments of secure access infrastructure. Organizations should also review their authentication and authorization policies to limit the scope of potential exploitation, as the vulnerability's effectiveness is directly tied to the authenticated user's access level within the system.