CVE-2017-3889 in Registered Envelope Service
Summary
by MITRE
A vulnerability in the web interface of the Cisco Registered Envelope Service could allow an unauthenticated, remote attacker to redirect a user to a undesired web page, aka an Open Redirect. This vulnerability affects the Cisco Registered Envelope cloud-based service. More Information: CSCvc60123. Known Affected Releases: 5.1.0-015.
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Analysis
by VulDB Data Team • 08/27/2020
The vulnerability identified as CVE-2017-3889 represents a critical security flaw in the web interface of Cisco Registered Envelope Service, a cloud-based communication platform designed for secure document sharing and collaboration. This weakness specifically manifests as an open redirect vulnerability that enables malicious actors to manipulate user navigation through crafted web requests. The issue affects version 5.1.0-015 of the service and demonstrates how seemingly benign web interface components can be exploited to create dangerous redirection scenarios that compromise user security and trust.
The technical implementation of this vulnerability stems from inadequate input validation within the web application's redirect functionality. When users interact with the service, the application processes redirect parameters without proper sanitization or validation, allowing attackers to inject malicious URLs into the redirect mechanism. This flaw operates at the application layer and can be exploited through simple HTTP requests containing crafted redirect parameters. The vulnerability is classified under CWE-601 as an Open Redirect vulnerability, which specifically addresses the risk of redirecting users to unintended destinations through unvalidated user input. The attack vector requires no authentication credentials, making it particularly dangerous as it can be exploited by any remote attacker with access to the vulnerable service.
The operational impact of this vulnerability extends beyond simple phishing attempts, creating a significant risk for organizations relying on Cisco Registered Envelope Service for secure communications. When exploited, the open redirect allows attackers to redirect users to malicious websites that can perform various harmful activities including credential harvesting, malware distribution, or social engineering attacks. The compromised trust relationship between users and the service can lead to broader security incidents, as users may unknowingly navigate to malicious sites while believing they are using legitimate service functionality. This vulnerability particularly affects organizations that handle sensitive data, as the redirect mechanism could be used to target specific user groups or to create convincing fake login pages that appear to be part of the legitimate service.
From an adversarial perspective, this vulnerability aligns with techniques documented in the MITRE ATT&CK framework under the T1566 category of "Phishing" and T1071.401 for "Application Layer Protocol: Web Protocols" where attackers leverage web application vulnerabilities to establish malicious redirections. The open redirect vulnerability can be combined with other attack vectors to create more sophisticated social engineering campaigns, where the initial redirect leads to a carefully crafted phishing page designed to capture user credentials or install malware. Organizations using the affected service should consider implementing network-level controls to monitor and block suspicious redirect patterns, while also ensuring that all users are educated about the risks of unexpected website redirections. The vulnerability highlights the importance of input validation and proper parameter handling in web applications, emphasizing that even minor implementation flaws can create significant security risks that affect user trust and data protection. Cisco has released patches and updates to address this vulnerability, and organizations should immediately implement these remediations to protect their users from potential exploitation.