Cisco · IOS and IOS XE Software
CVE-2018-0173
Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
What it is
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.
CISA: 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 can allow for denial-of-service (DoS).
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: March 17, 2022
- Added to the CISA list
- March 3, 2022
- Published
- March 28, 2018
- Severity
- High 8.6 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 7.6% in the top 5.5% of all known vulnerabilities
- Weakness
- CWE-20
- More details
- NVD · CVE.org · CISA
All references (6)
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2
- http://www.securityfocus.com/bid/103545
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
- https://www.tenable.com/security/research/tra-2018-06
- http://www.securitytracker.com/id/1040591
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
More exploited flaws from Cisco
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Apr 19, 2023 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 21% |
| Mar 3, 2022 | IOS Software and Cisco IOS XE Software UDP Packet Processing Denial-of-Service | IOS and IOS XE Software | High 7.5 | 6.2% |
| Mar 3, 2022 | IOS Software and Cisco IOS XE Software Denial-of-Service | IOS and IOS XE Software | Medium 6.5 | 2.1% |
| Mar 3, 2022 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 70% |
| Mar 3, 2022 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 45% |
| Mar 3, 2022 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 11% |
| Mar 3, 2022 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 11% |
| Mar 3, 2022 | SNMP Remote Code Execution | IOS and IOS XE Software | High 8.8 | 11% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.