CVE-2017-11344 in RT-AC68P
Summary
by MITRE
Global buffer overflow in networkmap in Asuswrt-Merlin firmware for ASUS devices and ASUS firmware for ASUS RT-AC5300, RT_AC1900P, RT-AC68U, RT-AC68P, RT-AC88U, RT-AC66U, RT-AC66U_B1, RT-AC58U, RT-AC56U, RT-AC55U, RT-AC52U, RT-AC51U, RT-N18U, RT-N66U, RT-N56U, RT-AC3200, RT-AC3100, RT_AC1200GU, RT_AC1200G, RT-AC1200, RT-AC53, RT-N12HP, RT-N12HP_B1, RT-N12D1, RT-N12+, RT_N12+_PRO, RT-N16, and RT-N300 devices allows remote attackers to write shellcode at any address in the heap; this can be used to execute arbitrary code on the router by hosting a crafted device description XML document at a URL specified within a Location header in an SSDP response.
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Analysis
by VulDB Data Team • 10/26/2019
The vulnerability identified as CVE-2017-11344 represents a critical buffer overflow flaw within the networkmap component of Asuswrt-Merlin firmware affecting numerous ASUS router models. This issue stems from improper input validation when processing device description XML documents, specifically within the Simple Service Discovery Protocol (SSDP) response handling mechanism. The flaw exists in the heap memory management of the affected firmware versions, creating a condition where remote attackers can manipulate memory allocation patterns through crafted network responses.
The technical implementation of this vulnerability occurs when the router processes an SSDP response containing a Location header that points to a maliciously crafted XML document. The networkmap component fails to properly bounds-check incoming data before copying it into fixed-size buffers, allowing attackers to overwrite adjacent memory locations. This heap-based buffer overflow enables arbitrary code execution with the privileges of the affected process, typically running with system-level permissions on the router. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though the heap manipulation aspect makes it particularly dangerous for persistent exploitation.
Operationally, this vulnerability presents a severe risk to network security as it allows remote code execution without requiring authentication or physical access to the device. Attackers can leverage this flaw by hosting malicious XML content on a remote server and triggering the vulnerable router to fetch and process the content through normal SSDP discovery mechanisms. The exploitation chain involves crafting a malicious SSDP response that includes a Location header pointing to the attacker-controlled XML file, which then triggers the buffer overflow during parsing. This creates a persistent threat vector that can be activated simply by having the vulnerable router discover and connect to the malicious network infrastructure.
The impact of this vulnerability extends beyond individual device compromise to potentially enable broader network infiltration and lateral movement. Once executed, the malicious code can establish persistent backdoors, modify router configurations, redirect network traffic, or serve as a launching point for attacks against other devices on the local network. Security researchers have documented this vulnerability as part of the ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter, specifically focusing on the use of shellcode execution within router environments. Organizations should consider implementing network segmentation, monitoring for unusual SSDP traffic patterns, and deploying intrusion detection systems to detect potential exploitation attempts.
Mitigation strategies for CVE-2017-11344 include immediate firmware updates from ASUS to patched versions that address the buffer overflow conditions in the networkmap component. Network administrators should also consider disabling unnecessary SSDP discovery services when possible and implementing firewall rules to restrict external SSDP traffic to trusted sources only. Additionally, regular security audits of network infrastructure should include verification of router firmware versions and implementation of network monitoring solutions capable of detecting anomalous XML processing behavior. The vulnerability demonstrates the importance of proper input validation and memory management in embedded systems, particularly those handling network protocols where external inputs can originate from untrusted sources without proper sanitization.