Linksys E1200

An OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and /hndUnblock.cgi endpoints over HTTP on port 8080. The CGI scripts improperly process user-supplied input passed to the ttcp_ip parameter without sanitization, allowing unauthenticated attackers to inject shell commands. This vulnerability was reported to be exploited in the wild by the "TheMoon" worm in 2014 to deploy a MIPS ELF payload, enabling arbitrary code execution on the router. Additionally, this vulnerability may affect other Linksys products to include, but not limited to, WAG/WAP/WES/WET/WRT-series router models and Wireless-N access points and routers. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.

A stack-based buffer overflow exists in the httpd binary of Linksys E1200 v2 routers (Firmware E1200_v2.0.11.001_us.tar.gz). The apply_cgi and block_cgi functions copy user-supplied input from the "url" CGI parameter into stack buffers (v36, v29) using sprintf without bounds checking. Because these buffers are allocated as single-byte variables, any non-empty input will trigger a buffer overflow. Remote attackers can exploit this vulnerability via crafted HTTP requests to execute arbitrary code or cause denial of service without authentication.

A stack-based buffer overflow exists in the get_merge_ipaddr function of the httpd binary on Linksys E1200 v2 routers (Firmware E1200_v2.0.11.001_us.tar.gz). The function concatenates up to four user-supplied CGI parameters matching <parameter>_0~3 into a fixed-size buffer (a2) without bounds checking. Remote attackers can exploit this vulnerability via specially crafted HTTP requests to execute arbitrary code or cause denial of service without authentication.

A stack-based buffer overflow vulnerability exists in the libshared.so library of Cisco Linksys E1200 v2 routers (Firmware E1200_v2.0.11.001_us.tar.gz). The functions get_mac_from_ip and get_ip_from_mac use sscanf with overly permissive "%100s" format specifiers to parse entries from /proc/net/arp into fixed-size buffers (v6: 50 bytes, v7 sub-arrays: 50 bytes). This allows local attackers controlling the contents of /proc/net/arp to overflow stack buffers, leading to memory corruption, denial of service, or potential arbitrary code execution.

Linksys E1000 devices through 2.1.02, E1200 devices before 2.0.05, and E3200 devices through 1.0.04 allow OS command injection via shell metacharacters in the apply.cgi ping_ip parameter on TCP port 52000.