CVE-2019-1876 in Wide Area Application Services
Summary
by MITRE
A vulnerability in the HTTPS proxy feature of Cisco Wide Area Application Services (WAAS) Software could allow an unauthenticated, remote attacker to use the Central Manager as an HTTPS proxy. The vulnerability is due to insufficient authentication of proxy connection requests. An attacker could exploit this vulnerability by sending a malicious HTTPS CONNECT message to the Central Manager. A successful exploit could allow the attacker to access public internet resources that would normally be blocked by corporate policies.
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Analysis
by VulDB Data Team • 10/07/2023
The vulnerability identified as CVE-2019-1876 resides within the HTTPS proxy functionality of Cisco Wide Area Application Services WAAS software, representing a critical security weakness that undermines the integrity of enterprise network protection mechanisms. This flaw specifically affects the Central Manager component which serves as the administrative interface for WAAS deployments, creating a pathway for unauthorized remote access through improperly validated proxy requests. The vulnerability stems from inadequate authentication controls that fail to properly verify the legitimacy of incoming proxy connection attempts, allowing malicious actors to bypass corporate security policies and gain unrestricted access to internet resources.
The technical exploitation of this vulnerability occurs through the manipulation of HTTPS CONNECT messages, which are standard HTTP requests used to establish proxy connections to remote servers. When an attacker crafts and sends a malicious CONNECT message to the Central Manager, the system fails to authenticate the request properly, effectively enabling the attacker to use the WAAS Central Manager as an unauthorized HTTPS proxy. This misconfiguration allows the malicious actor to route their network traffic through the corporate infrastructure without proper authorization, potentially accessing resources that should be blocked by corporate firewall policies and network security controls. The flaw operates at the application layer and leverages the fundamental trust relationship that exists between the WAAS Central Manager and legitimate proxy requests, making it particularly dangerous in enterprise environments where network segmentation and access controls are paramount.
The operational impact of this vulnerability extends beyond simple unauthorized internet access, as it fundamentally compromises the security posture of organizations relying on WAAS for application delivery and network optimization. Attackers could potentially access sensitive corporate data, exfiltrate information, or establish command and control channels through the compromised proxy functionality. The vulnerability's remote and unauthenticated nature means that attackers do not require valid credentials or physical access to the network to exploit it, making it particularly attractive for automated attacks. Organizations may experience significant compliance violations and security breaches as this vulnerability allows bypassing of standard corporate security measures including firewalls, content filters, and network access controls that are designed to prevent unauthorized internet access.
Mitigation strategies for CVE-2019-1876 should prioritize immediate patch deployment from Cisco, as the vulnerability requires software updates to address the underlying authentication flaw in the WAAS Central Manager's HTTPS proxy implementation. Network administrators should also implement additional protective measures including firewall rules that restrict access to the WAAS Central Manager from untrusted networks, network segmentation to isolate the Central Manager from public internet access, and enhanced monitoring of proxy-related traffic patterns for suspicious CONNECT requests. The vulnerability aligns with CWE-287, which addresses improper authentication issues in software systems, and represents a clear violation of the principle of least privilege as defined in cybersecurity best practices. From an ATT&CK framework perspective, this vulnerability maps to techniques involving proxy usage and command and control communications, potentially enabling lateral movement and data exfiltration operations that could significantly impact enterprise security posture and compliance requirements.