A remote code execution vulnerability exists in multiple Netcore and Netis routers models with firmware released prior to August 2014 due to the presence of an undocumented backdoor listener on UDP port 53413. Exact version boundaries remain undocumented. An unauthenticated remote attacker can send specially crafted UDP packets to execute arbitrary commands on the affected device. This backdoor uses a hardcoded authentication mechanism and accepts shell commands post-authentication. Some device models include a non-standard implementation of the `echo` command, which may affect exploitability.
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
| Link | Tags |
|---|---|
| https://web.archive.org/web/20140828114943/http://blog.trendmicro.com/trendlabs-security-intelligence/netis-routers-leave-wide-open-backdoor/ | third party advisory technical description |
| https://www.seebug.org/vuldb/ssvid-90227 | third party advisory technical description |
| https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/linux/misc/netcore_udp_53413_backdoor.rb | exploit |
| https://www.shadowserver.org/what-we-do/network-reporting/netcore-netis-router-vulnerability-scan-report/ | third party advisory |
| https://vulners.com/metasploit/MSF:EXPLOIT-LINUX-MISC-NETCORE_UDP_53413_BACKDOOR- | third party advisory exploit |
| https://www.vulncheck.com/advisories/netcore-netis-routers-backdoor-rce | third party advisory |
| https://www.exploit-db.com/exploits/43387 | exploit |