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CVE-2017-12240

Cisco — Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability

Cisco · CWE-20 — Improper input validation | CWE-119 · in CISA KEV since 2022-03-03

KEV since 2022 · listed over a yearCISA KEVActively Exploited
75

EVRS 75 of 100 Urgent

Patch This Cycle

Rank 972 of 2,960 tracked

Raised to the floor for a confirmed exploited vulnerability.

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Why it scores 75

Evidence available: 6 of 7 signals

Listed in the CISA KEV catalog, and an EPSS probability of 0.138.

  • CISA KEVApplied
  • RansomwareDid not apply
  • Vendor exploitationDid not apply
  • EPSSApplied
  • Microsoft Exploitability IndexNot applicable
  • Pre-patch disclosureNo data
  • KEV recencyDid not apply
  • CVSSApplied

The band answers “how soon”, not “how bad”. No data for: Pre-patch disclosure. Why some signals show no data

Fix

Patch or fixed version identified

CISA required action

Fixed in

ios: update to a version newer than 15.6

Affected versions

  • ios>= 12.2 <= 15.6
  • 1000 integrated services router
  • 1100-4g integrated services router
  • 1100-4gltegb integrated services router
  • 1100-4gltena integrated services router
  • 1100-4p integrated services router
  • 1100-6g integrated services router
  • 1100-8p integrated services router

+257 more affected products; see the full list at NVD.

Remediation

Apply updates per vendor instructions.

Fixed versions from NVD.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. 9.8 NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.138 (96.5th pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Confirmed CISA KEV
Ransomware campaign useWhether CISA has seen ransomware operators use it. Unknown or none CISA KEV
CISA remediation deadlineThe date US federal agencies must have fixed or mitigated it. 2022-03-24 · KEV since 2022 · listed over a year CISA KEV
Public exploit moduleA module existing is not the same as active exploitation. None known Metasploit
EUVD cross-referenceENISA's record: CVSS 9.8 (v3.1), assigned by cisco. Listed ENISA EUVD

Description

NVD

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.

What CISA says to do