CVE-2018-21178 in R7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR router models, specifically targeting the web management interface. The vulnerability arises from improper input validation within the device's authentication handling mechanisms, allowing an authenticated attacker to exploit memory corruption issues. The affected devices include popular models such as the R7800, R9000, and various WNDR series routers, all of which are susceptible due to insufficient bounds checking in their firmware implementations. This type of vulnerability falls under CWE-121 which specifically addresses stack-based buffer overflow conditions where insufficient space is allocated for data storage, leading to memory corruption. The vulnerability is particularly concerning because it requires only authentication, meaning that an attacker who has gained access to the device's administrative interface can leverage this flaw to execute arbitrary code or cause system instability.
The technical exploitation of this vulnerability occurs through crafted input parameters sent to the affected web interface endpoints. When an authenticated user submits maliciously formatted data to specific configuration pages, the device's processing routines fail to properly validate the input length against allocated buffer space. This allows attackers to overwrite adjacent memory locations on the stack, potentially corrupting return addresses and control flow information. The attack vector is particularly dangerous as it operates within the context of the authenticated session, meaning that an attacker who has already compromised administrative credentials could use this vulnerability to escalate privileges or gain deeper system access. According to ATT&CK framework, this vulnerability maps to T1068 which covers 'Exploitation for Privilege Escalation', and T1072 which addresses 'Software Deployment Tools', as the exploitation could potentially be used to deploy malicious firmware or tools.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it creates opportunities for persistent system compromise and potential network-wide attacks. An attacker who successfully exploits this vulnerability could gain complete administrative control over the affected router, potentially using it as a pivot point for attacking other devices within the local network. The affected firmware versions span multiple generations of NETGEAR routers, indicating a widespread issue that could impact thousands of devices in enterprise and home network environments. Network security teams should consider this vulnerability as a high-priority threat due to the combination of authenticated access requirements and the potential for privilege escalation. The vulnerability also represents a significant concern for organizations using these devices as part of their network infrastructure, as compromised routers could provide attackers with unauthorized access to internal network resources and potentially serve as entry points for broader network infiltration activities.
Mitigation strategies should focus on immediate firmware updates from NETGEAR, as the vendor has released patches addressing this specific buffer overflow condition. Organizations should also implement network segmentation to limit the potential impact of a compromised device and monitor for unusual network traffic patterns that might indicate exploitation attempts. Additionally, network administrators should consider disabling unnecessary web management interfaces when not actively required and ensure that strong authentication mechanisms are in place to prevent unauthorized access to administrative functions. The vulnerability highlights the importance of regular firmware updates and proper input validation in network device software development, particularly when dealing with user-controllable data in web-based administrative interfaces. Security professionals should also be aware that similar vulnerabilities may exist in other network device firmware implementations, making this a valuable indicator for broader security assessments of network infrastructure components.