CVE-2017-17947 in Pulse Connect Secure
Summary
by MITRE
A cross site scripting issue has been found in custompage.cgi in Pulse Secure Pulse Connect Secure (PCS) before 8.0R17.0, 8.1.x before 8.1R13, 8.2.x before 8.2R9, and 8.3.x before 8.3R3 and Pulse Policy Secure (PPS) before 5.2R10, 5.3.x before 5.3R9, and 5.4.x before 5.4R3 due to one of the URL parameters not being sanitized. Exploitation does require the user to be logged in as administrator; the issue is not applicable to the end user portal.
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Analysis
by VulDB Data Team • 12/23/2019
The vulnerability identified as CVE-2017-17947 represents a critical cross site scripting flaw in Pulse Secure's Pulse Connect Secure and Pulse Policy Secure products, affecting multiple version ranges across different product lines. This vulnerability specifically targets the custompage.cgi component within these security appliances, which are widely deployed for remote access and network security management. The issue stems from insufficient input validation and sanitization of URL parameters, creating an avenue for malicious code injection that could be exploited by authenticated administrators. The vulnerability's impact is particularly concerning given the privileged nature of the affected users, as exploitation requires administrative login credentials, making it a significant risk for organizations relying on these security platforms.
The technical implementation of this vulnerability resides in the improper handling of user-supplied input within the custompage.cgi script, which processes URL parameters without adequate sanitization mechanisms. According to CWE classification, this represents a CWE-79: Cross-site Scripting vulnerability where the application fails to validate or escape user input before incorporating it into dynamically generated web content. The flaw allows attackers with administrative access to inject malicious scripts that execute in the context of other administrators' browsers, potentially enabling session hijacking, privilege escalation, or data exfiltration. The ATT&CK framework categorizes this as a web application vulnerability that could be leveraged for initial access or lateral movement within compromised networks, particularly when combined with other exploitation techniques.
Operational impact of this vulnerability extends beyond simple script injection, as it could enable attackers to manipulate the administrative interface of security appliances, potentially compromising the integrity of network security policies and configurations. The requirement for administrator authentication limits the scope of exploitation but does not eliminate the severity, as administrative credentials are often more valuable and harder to protect than regular user accounts. Organizations using affected versions face risks including unauthorized access to sensitive network configurations, potential data breaches through session manipulation, and the possibility of attackers using the compromised administrative interface to establish persistent access. The vulnerability affects multiple product versions simultaneously, indicating a systemic issue in the input validation implementation across different releases.
Mitigation strategies for CVE-2017-17947 should prioritize immediate patching of affected systems to the latest available versions, specifically targeting the release versions mentioned in the advisory. Organizations should implement network segmentation to limit access to administrative interfaces and enforce strict access controls using multi-factor authentication for administrative accounts. Additionally, regular security assessments and input validation reviews should be conducted to identify similar vulnerabilities in other applications within the network infrastructure. The vulnerability highlights the importance of maintaining up-to-date security appliances and implementing comprehensive security monitoring to detect potential exploitation attempts. Network administrators should also consider implementing web application firewalls and regular input validation testing to prevent similar issues from arising in other components of their security infrastructure.