CVE-2021-45638 in D6220
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by a stack-based buffer overflow by an unauthenticated attacker. This affects D6220 before 1.0.0.68, D6400 before 1.0.0.102, D7000v2 before 1.0.0.74, D8500 before 1.0.3.60, DC112A before 1.0.0.56, R6300v2 before 1.0.4.50, R6400 before 1.0.1.68, R7000 before 1.0.11.116, R7100LG before 1.0.0.70, RBS40V before 2.6.2.8, RBW30 before 2.6.2.2, RS400 before 1.5.1.80, R7000P before 1.3.2.132, and R6900P before 1.3.2.132.
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Analysis
by VulDB Data Team • 12/28/2021
This vulnerability represents a critical stack-based buffer overflow condition affecting multiple NETGEAR networking devices that operate under the assumption of unauthenticated remote exploitation. The flaw exists within the firmware implementations of various router models including D6220, D6400, D7000v2, and numerous other devices in the R6300v2, R6400, R7000, and R7000P series. The vulnerability stems from improper bounds checking in network protocol handling routines where input data exceeding allocated stack buffer space can overwrite adjacent memory locations. This condition allows an attacker to manipulate program execution flow through controlled memory corruption, potentially leading to arbitrary code execution or system compromise. The affected firmware versions span several years of releases indicating this vulnerability has persisted across multiple product generations without adequate mitigation.
The technical exploitation of this vulnerability aligns with CWE-121 Stack-based Buffer Overflow, a well-documented weakness category that has been classified under the Common Weakness Enumeration framework. The attack vector requires no authentication, making it particularly dangerous as it can be exploited remotely by any attacker with network access to the affected devices. This characteristic places the vulnerability within the ATT&CK framework's T1210 - Exploitation of Remote Services, where adversaries leverage unpatched network services to gain system access. The stack overflow occurs during normal network protocol processing when the device receives malformed input data through standard network communication channels, typically HTTP or Telnet services that are enabled on these devices.
The operational impact of this vulnerability extends beyond simple device compromise to encompass potential network-wide security breaches. An unauthenticated attacker can leverage this vulnerability to execute arbitrary code on the affected devices, potentially leading to complete system takeover, data exfiltration, or the establishment of persistent backdoors. The affected devices serve as network gateways, making their compromise particularly dangerous as it could provide attackers with access to internal network segments. The vulnerability affects both consumer and small business networking equipment, creating widespread exposure across numerous network environments. Additionally, the presence of this vulnerability in multiple firmware versions suggests that network administrators may have been unaware of the risk across their entire device inventory, complicating remediation efforts.
Mitigation strategies should prioritize immediate firmware updates from NETGEAR to address the identified buffer overflow conditions, with particular attention to the affected device models and their respective firmware version requirements. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while disabling unnecessary services such as remote management capabilities where possible. Security monitoring should include detection of anomalous network traffic patterns that might indicate exploitation attempts, particularly around HTTP and Telnet service ports. The vulnerability demonstrates the importance of proper input validation and bounds checking in embedded networking devices, reinforcing industry best practices around secure coding standards and regular security assessments of network infrastructure components. Organizations should also consider implementing network intrusion detection systems to identify potential exploitation attempts and maintain comprehensive inventory tracking of all networked devices to ensure timely patch deployment across all affected systems.