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Cisco Network Convergence System 4000 Series TL1 Denial of Service Vulnerability

cisco-sa-ncs4k-tl1-GNnLwC6 · Medium · Published · Updated

A vulnerability in the TL1 function of Cisco Network Convergence System (NCS) 4000 Series could allow an authenticated, local attacker to cause a memory leak in the TL1 process. This vulnerability is due to TL1 not freeing memory under some conditions. An attacker could exploit this vulnerability by connecting to the device and issuing TL1 commands after being authenticated. A successful exploit could allow the attacker to cause the TL1 process to consume large amounts of memory. When the memory reaches a threshold, the Resource Monitor (Resmon) process will begin to restart or shutdown the top five consumers of memory, resulting in a denial of service (DoS). 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-ncs4k-tl1-GNnLwC6 This advisory is part of the September 2022 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2022 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication.

Cisco advisory ·CSAF JSON

Workarounds

There are no workarounds that address this vulnerability. However, administrators can monitor the memory that is held by the TL1 process and restart it if it reaches about 400MB. To obtain the current TL1 memory holdings, issue the show processes memory command. If memory exceeds 400MB, restart the TL1 process, as shown in the following example:

RP/0/RP0:NCS4000#show processes memory | include tl1
Tue Sep 06 18:52:49.658 EST
175 532 624248 212 299563 tl1
152 244 77696 136 3439 tl1_parser
RP/0/RP0:NCS4000#
RP/0/RP0:NCS4000#process restart tl1

While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

CVEsCVE-2022-20845
Cisco Bug IDsCSCwb01669, CSCwb16005
CVSS ScoreBase 6.0
Base 6.0 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Product Names From Source
Cisco IOS XR Software

Related Products

Product CVE Evidence
Cisco RV Series Routers CVE-2022-20845 Cisco OpenVuln
Cisco Nexus Dashboard CVE-2022-20845 Cisco OpenVuln
Cisco Network Convergence System 4000 Series CVE-2022-20845 Cisco OpenVuln
Cisco IOS Software CVE-2022-20845 Cisco OpenVuln
Cisco Catalyst PON Series Switches CVE-2022-20845 Cisco OpenVuln
Cisco IOS XR Software CVE-2022-20845 Cisco OpenVuln
Cisco IOS CVE-2022-20845 Cisco OpenVuln