Detections
Analytics
Cisco IOS XR Software DHCP Version 4 Server DoS (cisco-sa-iosxr-dhcp-dos-pjPVReLU)
high Nessus Plugin ID 153207
Language:
Synopsis
The remote device is missing a vendor-supplied security patchDescription
According to its self-reported version, Cisco IOS XR is affected by a vulnerability in the DHCP version 4 (DHCPv4) server feature that allows an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a NULL pointer dereference, resulting in a crash of the dhcpd process. While the dhcpd process is restarting, which may take up to approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period. Note: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload.Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Solution
Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvw95930See Also
http://www.nessus.org/u?ce07f05c
http://tools.cisco.com/security/center/viewErp.x?alertId=ERP-74637
Plugin Details
Severity: High
ID: 153207
File Name: cisco-sa-iosxr-dhcp-dos-pjPVReLU-iosxr.nasl
Version: 1.7
Type: combined
Family: CISCO
Published: 9/10/2021
Updated: 4/22/2022
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Low
Score: 3.6
CVSS v2
Risk Factor: Medium
Base Score: 5
Temporal Score: 3.7
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS Score Source: CVE-2021-34737
CVSS v3
Risk Factor: High
Base Score: 7.5
Temporal Score: 6.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:cisco:ios_xr
Required KB Items: Host/Cisco/IOS-XR/Version, Host/Cisco/IOS-XR/Model
Exploit Ease: No known exploits are available
Patch Publication Date: 9/8/2021
Vulnerability Publication Date: 9/8/2021
Reference Information
CVE: CVE-2021-34737