cisco-sa-20180328-dhcpr2: Cisco IOS and IOS XE Software DHCP Version 4 Relay Reply Denial of Service Vulnerability
First published: Wed Mar 28 2018(Updated: )
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 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 has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2 This advisory is part of the March 28, 2018, release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication, which includes 20 Cisco Security Advisories that describe 22 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: March 2018 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
Credit: Tenable for finding reporting this vulnerability.
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cisco IOS | ||
| Cisco IOS XE Software |
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Reference Links
Frequently Asked Questions
What is the severity of cisco-sa-20180328-dhcpr2?
The severity of cisco-sa-20180328-dhcpr2 is categorized as high due to its potential for remote denial of service.
How do I fix cisco-sa-20180328-dhcpr2?
To fix cisco-sa-20180328-dhcpr2, update your affected Cisco IOS or IOS XE Software to the latest version as recommended by Cisco.
What devices are affected by cisco-sa-20180328-dhcpr2?
cisco-sa-20180328-dhcpr2 affects devices running Cisco IOS Software and Cisco IOS XE Software that utilize DHCP functions.
What type of attack can be executed with cisco-sa-20180328-dhcpr2?
An unauthenticated remote attacker can exploit cisco-sa-20180328-dhcpr2 to cause affected devices to reload, resulting in a denial of service.
Is authentication required to exploit cisco-sa-20180328-dhcpr2?
No authentication is required to exploit cisco-sa-20180328-dhcpr2, making it particularly dangerous.
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