Attack vector
ADJACENT_NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Published: 2020-03-25
Updated: 2023-02-03
Summary
This vulnerability allows network-adjacent 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 tdpServer service, which listens on UDP port 20002 by default. When parsing the slave_mac parameter, the process does not properly validate a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of the root user. Was ZDI-CAN-9650.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Command Line Execution through SQL Injection
An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
- Command Delimiters
An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or a blacklist input validation, as opposed to whitelist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or blacklist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
- Exploiting Multiple Input Interpretation Layers
An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
- Argument Injection
An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
- OS Command Injection
In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.
Exploit-Db
id | EDB-ID:48331 |
last seen | 2020-04-16 |
modified | 2020-04-16 |
published | 2020-04-16 |
reporter | Exploit-DB |
source | https://www.exploit-db.com/download/48331 |
title | TP-Link Archer A7/C7 - Unauthenticated LAN Remote Code Execution (Metasploit) |
Metasploit
description | This module exploits a command injection vulnerability in the tdpServer daemon (/usr/bin/tdpServer), running on the router TP-Link Archer A7/C7 (AC1750), hardware version 5, MIPS Architecture, firmware version 190726. The vulnerability can only be exploited by an attacker on the LAN side of the router, but the attacker does not need any authentication to abuse it. After exploitation, an attacker will be able to execute any command as root, including downloading and executing a binary from another host. This vulnerability was discovered and exploited at Pwn2Own Tokyo 2019 by the Flashback team (Pedro Ribeiro + Radek Domanski). |
id | MSF:EXPLOIT/LINUX/MISC/TPLINK_ARCHER_A7_C7_LAN_RCE |
last seen | 2020-06-12 |
modified | 2020-04-16 |
published | 2020-04-07 |
references | |
reporter | Rapid7 |
source | https://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/linux/misc/tplink_archer_a7_c7_lan_rce.rb |
title | TP-Link Archer A7/C7 Unauthenticated LAN Remote Code Execution |