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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2017-12240

Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability

KEVCRITICAL 9.8EPSS 13.9%

Does this matter?

Known to be exploited in the wild (CISA KEV, CISA remediation deadline 24 March 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.

Description

The DHCP relay subsystem of Cisco IOS 12.2 through 15.6 and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition. Cisco Bug IDs: CSCsm45390, CSCuw77959.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
13.88% probability · 96th percentile
CISA KEV
Listed 3 March 2022 · due 24 March 2022
Weakness
CWE-20, CWE-119
Affected
cisco/ios
Source
psirt@cisco.com

CISA notes

Apply updates per vendor instructions. https://nvd.nist.gov/vuln/detail/CVE-2017-12240

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.