CVE-2020-10885 in AC1750
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on affected installations of TP-Link Archer A7 Firmware Ver: 190726 AC1750 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of DNS responses. The issue results from the lack of proper validation of DNS reponses prior to further processing. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the root user. Was ZDI-CAN-9661.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 05/11/2024
The CVE-2020-10885 vulnerability represents a critical remote code execution flaw in TP-Link Archer A7 routers running firmware version 190726 with AC1750 capabilities. This vulnerability operates at the network layer through DNS response handling mechanisms, making it particularly dangerous as it requires no authentication for exploitation. The flaw stems from insufficient input validation within the router's DNS processing subsystem, creating an attack vector that can be leveraged by remote adversaries without prior access credentials. The vulnerability's classification aligns with CWE-20, which describes improper input validation, and demonstrates how inadequate sanitization of network responses can lead to system compromise. This issue falls under the ATT&CK technique T1219, where adversaries use remote services to gain initial access or execute malicious code.
The technical implementation of this vulnerability occurs when the router receives and processes DNS responses without adequate validation checks. The device fails to properly validate the integrity and legitimacy of DNS replies before incorporating them into its routing decisions or system operations. This lack of validation creates a pathway for attackers to craft malicious DNS responses that, when processed by the vulnerable router, trigger unintended code execution. The vulnerability's exploitation typically involves sending specially crafted DNS packets that contain malicious payloads or malformed data structures designed to exploit buffer overflows or other memory corruption issues within the router's DNS handling code. The root user context execution capability indicates that successful exploitation bypasses normal user permissions and directly elevates privileges within the router's operating system.
The operational impact of CVE-2020-10885 extends beyond simple remote code execution, as it provides attackers with complete control over the affected router's functionality. Once exploited, adversaries can modify network configurations, redirect traffic through malicious servers, install persistent backdoors, or use the compromised device as a pivot point for attacking other systems within the local network. The vulnerability's severity is amplified by its ability to be exploited remotely, meaning attackers can compromise devices from anywhere on the internet without requiring physical access or network proximity. This makes the vulnerability particularly concerning for enterprise environments where router security is often overlooked in favor of more visible network endpoints. The lack of authentication requirements significantly reduces the attack surface and increases the likelihood of successful exploitation.
Mitigation strategies for CVE-2020-10885 should prioritize immediate firmware updates from TP-Link, as the vendor has likely released patches addressing the DNS validation issues. Network administrators should implement DNS filtering and monitoring solutions to detect anomalous DNS responses that might indicate exploitation attempts. The implementation of network segmentation and access control lists can help limit the potential damage if a device becomes compromised. Regular security assessments of network infrastructure should include vulnerability scanning for similar DNS-related issues across all router models. Organizations should also consider deploying intrusion detection systems specifically configured to monitor for DNS tunneling and other malicious DNS activities. The vulnerability's characteristics align with ATT&CK tactics involving initial access and privilege escalation, making comprehensive network monitoring and endpoint detection critical defensive measures. Security teams should also implement regular patch management procedures to ensure all network devices receive timely updates addressing known vulnerabilities.