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Actively exploited · Published Mar 17, 2017 · Assigned by cisco

CVE-2017-3881

Critical 9.8 Exploited

In plain English

A critical-severity improper input validation in Cisco IOS and IOS XE Software. Attackers are actively exploiting it in the wild (listed by CISA on March 25, 2022). The chance it is exploited in the next 30 days is estimated at 99.0% (higher than 99.9% of all known vulnerabilities). Ready-made attack tooling exists: Metasploit, Nuclei, public proof-of-concept code. Apply updates per vendor instructions.

Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)99.0%top 0.1% of all CVEs
Exploited in the wildYesCISA KEV since Mar 25, 2022
Attack tooling3Metasploit, Nuclei, Public PoC

CISA guidance

Apply updates per vendor instructions.

Federal agencies must remediate by Apr 15, 2022.

Official description

A vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges. The Cluster Management Protocol utilizes Telnet internally as a signaling and command protocol between cluster members. The vulnerability is due to the combination of two factors: (1) 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 (2) 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. This affects Catalyst switches, Embedded Service 2020 switches, Enhanced Layer 2 EtherSwitch Service Module, Enhanced Layer 2/3 EtherSwitch Service Module, Gigabit Ethernet Switch Module (CGESM) for HP, IE Industrial Ethernet switches, ME 4924-10GE switch, RF Gateway 10, and SM-X Layer 2/3 EtherSwitch Service Module. Cisco Bug IDs: CSCvd48893.

Affected products (as reported)

VendorProductVersions
n/a Cisco IOS and IOS XE Software Cisco IOS and IOS XE Software

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References