CVE-2017-5571 in FlexNet Publisher
Summary
by MITRE
Open redirect vulnerability in the lmadmin component in Flexera FlexNet Publisher (aka Flex License Manager) 11.14.1 and earlier, as used in Citrix License Server for Windows and the Citrix License Server VPX, allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 08/26/2024
The vulnerability CVE-2017-5571 represents an open redirect flaw within the lmadmin component of Flexera FlexNet Publisher version 11.14.1 and earlier, which is integrated into Citrix License Server for Windows and Citrix License Server VPX environments. This security weakness enables remote attackers to manipulate the application's redirect functionality, potentially directing users to malicious websites and facilitating phishing attacks. The vulnerability exists in the license management component that handles administrative functions, creating a pathway for attackers to exploit user trust in legitimate applications.
The technical implementation of this open redirect vulnerability stems from inadequate input validation and sanitization within the lmadmin interface. Attackers can craft malicious URLs containing redirect parameters that bypass proper validation checks, allowing arbitrary redirection to attacker-controlled domains. This flaw operates by accepting user-supplied redirect targets without sufficient verification of their legitimacy, creating a trust relationship that can be exploited. The vulnerability is classified under CWE-601 as an Open Redirect vulnerability, where the application's redirect mechanism fails to validate the destination URL against a whitelist of approved domains. The attack vector typically involves sending crafted links to users through social engineering techniques, leveraging the legitimate application's interface to appear trustworthy.
The operational impact of this vulnerability extends beyond simple phishing attempts, as it can enable more sophisticated attack chains within enterprise environments. When exploited successfully, attackers can redirect users to malicious sites that appear to be legitimate Citrix license server interfaces, potentially capturing credentials or installing malware. This vulnerability particularly affects organizations using Citrix License Server solutions, where the administrative interface is accessible over network connections. The threat landscape is amplified because the vulnerability exists in widely deployed license management software, making it an attractive target for adversaries seeking to compromise enterprise licensing infrastructure. The open redirect can be leveraged in conjunction with other attacks to establish persistent access or escalate privileges within the affected environment.
Organizations should implement immediate mitigations including applying the vendor-provided patches for FlexNet Publisher versions 11.15 and later, which address the redirect validation issues. Network segmentation and access controls should be enforced to limit exposure of the lmadmin interface to trusted networks only. Implementing web application firewalls with URL validation capabilities can provide additional protection layers. Security monitoring should include detection of suspicious redirect patterns in network traffic and application logs. The vulnerability aligns with ATT&CK technique T1566 for phishing and T1071 for application layer protocol usage, demonstrating how open redirect vulnerabilities can serve as initial access vectors in broader attack campaigns. Regular security assessments and penetration testing should verify that redirect mechanisms properly validate destination URLs against approved domains to prevent similar issues in other components.