CVE-2019-11538 in Pulse Connect Secure
Summary
by MITRE
In Pulse Secure Pulse Connect Secure version 9.0RX before 9.0R3.4, 8.3RX before 8.3R7.1, 8.2RX before 8.2R12.1, and 8.1RX before 8.1R15.1, an NFS problem could allow an authenticated attacker to access the contents of arbitrary files on the affected device.
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Analysis
by VulDB Data Team • 09/07/2023
The vulnerability identified as CVE-2019-11538 represents a critical file access flaw within Pulse Secure Pulse Connect Secure appliances that affected multiple version branches including 9.0RX, 8.3RX, 8.2RX, and 8.1RX. This issue stems from an insecure implementation of Network File System (NFS) functionality that permits authenticated attackers to bypass normal access controls and retrieve arbitrary files from the affected device's file system. The vulnerability specifically impacts appliances running versions prior to the mentioned patches, creating a persistent security risk for organizations relying on these network access solutions.
The technical root cause of this vulnerability lies in the improper handling of NFS requests within the Pulse Connect Secure software implementation. When authenticated users interact with the NFS service, the system fails to properly validate file access requests, allowing malicious actors to craft specific NFS operations that traverse the file system hierarchy without proper authorization. This flaw enables attackers to access sensitive system files, configuration data, and potentially confidential information stored on the appliance. The vulnerability operates at the file system level, making it particularly dangerous as it can expose system internals that might contain credentials, cryptographic keys, or other sensitive operational data.
The operational impact of CVE-2019-11538 extends beyond simple unauthorized file access, as it provides attackers with potential pathways to escalate their privileges and compromise the entire network access infrastructure. Organizations using affected Pulse Connect Secure appliances face significant risks including data exfiltration, system reconnaissance, and potential lateral movement within their networks. The vulnerability's impact is amplified by the fact that it requires only authentication to exploit, meaning that an attacker who can establish a valid session with the appliance can leverage this flaw to access sensitive system information. This characteristic aligns with attack patterns documented in the MITRE ATT&CK framework under techniques related to privilege escalation and credential access, specifically targeting the credential access tactic and privilege escalation sub-techniques.
Organizations should prioritize immediate patching of all affected Pulse Connect Secure appliances to remediate this vulnerability, as the window for exploitation remains open for systems running unsupported versions. The recommended mitigation strategy involves applying the vendor-provided security patches that address the NFS implementation flaws and ensure proper file access controls are enforced. Additionally, network segmentation and monitoring of NFS traffic can provide additional defensive layers, though these measures do not address the core vulnerability. Security teams should also conduct comprehensive audits of affected systems to identify any potential compromise indicators and review access logs for suspicious activity related to NFS operations. This vulnerability demonstrates the importance of maintaining current security patches for network infrastructure components and highlights how seemingly minor implementation flaws in system services can create significant security risks that may affect entire organizational networks.