CVE-2016-7560 in FortiWLC
Summary
by MITRE
The rsyncd server in Fortinet FortiWLC 6.1-2-29 and earlier, 7.0-9-1, 7.0-10-0, 8.0-5-0, 8.1-2-0, and 8.2-4-0 has a hardcoded rsync account, which allows remote attackers to read or write to arbitrary files via unspecified vectors.
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Analysis
by VulDB Data Team • 05/03/2019
The vulnerability identified as CVE-2016-7560 affects the rsyncd server component within Fortinet FortiWLC wireless LAN controllers running specific firmware versions. This issue represents a critical authentication flaw that undermines the security posture of affected devices by introducing a hardcoded account that persists across multiple software releases. The vulnerability specifically impacts versions 6.1-2-29 and earlier, as well as several 7.0 and 8.0 series releases, indicating a widespread exposure across the product lineage. The presence of hardcoded credentials in network infrastructure devices creates a persistent security risk that can be exploited by remote attackers without requiring prior authentication or knowledge of legitimate user credentials.
The technical flaw manifests through the implementation of a hardcoded rsync account within the rsyncd server configuration, which operates as a daemon service responsible for file synchronization tasks. This hardcoded account bypasses normal authentication mechanisms and provides unauthorized access to the underlying file system through unspecified attack vectors that likely involve network-based exploitation of the rsync service. The vulnerability falls under the category of credential exposure and weak authentication as classified by CWE-798, where hardcoded credentials are stored in the application source code or configuration files. The rsync protocol itself is designed for secure file synchronization, but the presence of a hardcoded account eliminates the security benefits typically associated with proper authentication mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data compromise and system integrity violations. Remote attackers can leverage this hardcoded account to read or write to arbitrary files on the affected systems, which could include configuration files, log data, system binaries, or sensitive user information. This capability allows for privilege escalation and persistence within the network infrastructure, potentially enabling attackers to establish backdoors or exfiltrate confidential data. The vulnerability's classification under ATT&CK technique T1078.004 highlights the exploitation of valid accounts for unauthorized access, while also potentially mapping to T1566 for initial access through network services. The attack surface is further expanded as rsyncd servers are often configured to provide access to network shares and file systems, making the compromise of such services particularly dangerous for enterprise environments.
Mitigation strategies for CVE-2016-7560 must address both immediate remediation and long-term security hardening of the affected Fortinet devices. The primary recommendation involves upgrading to firmware versions that contain the necessary patches to remove or properly secure the hardcoded rsync account. Organizations should also implement network segmentation to limit access to rsync services and disable unnecessary rsync functionality when not required for business operations. Security monitoring should be enhanced to detect unusual rsync activity patterns that might indicate exploitation attempts, while regular vulnerability assessments should be conducted to identify other potential hardcoded credentials or weak authentication mechanisms. The vulnerability demonstrates the critical importance of proper credential management and configuration hardening practices, aligning with security frameworks that emphasize the principle of least privilege and the elimination of default or hardcoded credentials in production environments. Additionally, implementing network access controls and firewall rules to restrict rsync service access to only trusted sources can provide additional defense-in-depth measures against exploitation attempts.