#VU56425 Improper Verification of Cryptographic Signature in Cisco 8000 Series Routers and Cisco Network Convergence System 540 Series Routers - CVE-2021-34709

Vulnerability identifier: #VU56425

Vulnerability risk: Low

CVSSv4.0: 5.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-34709

CWE-ID: CWE-347

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Cisco 8000 Series Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc
Cisco Network Convergence System 540 Series Routers
Hardware solutions / Routers & switches, VoIP, GSM, etc

Vendor: Cisco Systems, Inc

Description

The vulnerability allows a local administrator to execute arbitrary code on the system. 

The vulnerability exists in the Cisco IOS XR due to a race condition that occurs when the install request is being processed. A local administrator can modify an ISO image and execute arbitrary code on the affected device. 

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Cisco 8000 Series Routers: before 7.3.2

Cisco Network Convergence System 540 Series Routers: before 7.3.2

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External links
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-lnt-QN9mCzwn

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.