Cisco patched a critical vulnerability, one that was disclosed in the Vault 7 hacking tools leak, that left dozens of the company’s switches open to being compromised.
The flaw, CVE-2017-3881, impacts Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software that if left unpatched could allow an attacker to remotely executive code.
Cisco said the flaw is due to a combination of two issues.
The failure to restrict the use of CMP-specific Telnet options only to internal, local communications between cluster members and instead accept and process such options over any Telnet connection to an affected device, and the incorrect processing of malformed CMP-specific Telnet options.
“An attacker could exploit this vulnerability by sending malformed CMP-specific Telnet options while establishing a Telnet session with an affected Cisco device configured to accept Telnet connections. An exploit could allow an attacker to execute arbitrary code and obtain full control of the device or cause a reload of the affected device,” Cisco wrote.