CVE-2020-15069 in XG Firewall
Summary
by MITRE
Sophos XG Firewall 17.x through v17.5 MR12 allows a Buffer Overflow and remote code execution via the HTTP/S Bookmarks feature for clientless access. Hotfix HF062020.1 was published for all firewalls running v17.x.
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Analysis
by VulDB Data Team • 02/06/2025
The Sophos XG Firewall vulnerability CVE-2020-15069 represents a critical buffer overflow flaw within the HTTP/S Bookmarks feature that enables clientless access to the firewall interface. This vulnerability affects versions 17.x through v17.5 MR12 of the Sophos XG Firewall software, creating a significant security risk for organizations relying on these network protection systems. The flaw specifically resides in how the firewall processes HTTP/S bookmark requests, allowing malicious actors to exploit the buffer overflow condition through carefully crafted input data.
The technical implementation of this vulnerability involves the improper handling of user-supplied data within the bookmark processing functionality. When a remote attacker submits maliciously formatted HTTP/S bookmark requests, the firewall's input validation mechanisms fail to properly sanitize the data, leading to a buffer overflow condition in memory. This type of vulnerability maps directly to CWE-121, which describes buffer overflow conditions where insufficient space is allocated for data storage, and CWE-125, which covers out-of-bounds read vulnerabilities. The buffer overflow occurs within the application's memory management routines, specifically in the handling of HTTP header data or bookmark parameters, allowing attackers to overwrite adjacent memory locations.
The operational impact of this vulnerability extends beyond simple exploitation, as it enables remote code execution without requiring authentication or prior access to the network. Attackers can leverage this flaw to execute arbitrary code on the affected firewall system, potentially gaining complete control over the network security infrastructure. This compromise could lead to unauthorized network access, data exfiltration, man-in-the-middle attacks, and complete network disruption. The vulnerability's remote nature makes it particularly dangerous as attackers can exploit it from outside the network perimeter, making it a prime target for advanced persistent threats and cybercriminal operations. Organizations running affected versions face immediate risk of network compromise, with potential lateral movement opportunities through the compromised firewall.
Mitigation strategies for CVE-2020-15069 should prioritize the immediate installation of the published hotfix HF062020.1, which addresses the buffer overflow condition in the HTTP/S Bookmarks feature. Network administrators should also implement additional security measures including disabling the clientless access functionality if not required, implementing strict network segmentation, and monitoring for suspicious HTTP/S bookmark requests. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1071 for application layer protocol, highlighting the potential for attackers to establish persistent access and conduct further reconnaissance. Organizations should also conduct comprehensive vulnerability assessments to identify any other potentially affected systems and ensure proper patch management processes are in place to prevent similar vulnerabilities from being exploited in the future.