Improper input validation in Cisco 4321 Integrated Services Router
CVE-2018-0173
A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvg62754.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.077 (94.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
Affected products
- Cisco 4321_integrated_services_router
- Cisco 4331_integrated_services_router
- Cisco 4351_integrated_services_router
- Cisco 4431_integrated_services_router
- Cisco 4451-x_integrated_services_router
- Cisco Asr_1000_series_route_processor_\(rp2\)
- Cisco Asr_1000_series_route_processor_\(rp3\)
- Cisco Asr_1001-hx
- Cisco Asr_1001-x
- Cisco Asr_1002-hx
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply updates per vendor instructions.
Public proof-of-concept exploits
References
- psirt@cisco.com (x_refsource_CONFIRM, Vendor Advisory)
- psirt@cisco.com (VDB Entry, Third Party Advisory, vdb-entry, Broken Link, x_refsource_BID)
- psirt@cisco.com (US Government Resource, Third Party Advisory, x_refsource_MISC)
- psirt@cisco.com (Third Party Advisory, x_refsource_MISC)
- psirt@cisco.com (VDB Entry, Third Party Advisory, vdb-entry, x_refsource_SECTRACK, Broken Link)
- psirt@cisco.com (US Government Resource, Third Party Advisory, x_refsource_MISC)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
Frequently asked questions
- What is CVE-2018-0173?
- CVE-2018-0173 is a high-severity vulnerability in Cisco 4321 Integrated Services Router, classified under Improper Input Validation. CVSS score: 8.6/10. Published 2018-03-28.
- How severe is CVE-2018-0173?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2018-0173 known to be exploited?
- Yes. CVE-2018-0173 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-03), indicating it is being actively exploited. 2 public proof-of-concept repositories are indexed.