Improper image signature verification in Cisco IOS XR
| Risk | Low |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2021-1136 CVE-2021-1244 |
| CWE-ID | CWE-347 |
| Exploitation vector | Local |
| Public exploit | N/A |
| Vulnerable software |
Cisco 8000 Series Routers Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco Network Convergence System 5000 Series Hardware solutions / Routers & switches, VoIP, GSM, etc Cisco ASR 9000 Series Aggregation Services Routers Hardware solutions / Routers & switches, VoIP, GSM, etc |
| Vendor | Cisco Systems, Inc |
Security Bulletin
This security bulletin contains information about 2 vulnerabilities.
1) Improper verification of cryptographic signature
EUVDB-ID: #VU50379
Risk: Low
CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2021-1136
CWE-ID:
CWE-347 - Improper Verification of Cryptographic Signature
Exploit availability: No
DescriptionThe vulnerability allows a local user to bypass implemented security restrictions.
The vulnerability exists in the signing functions of ISO packaging of Cisco NCS 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for the Cisco 8000 Series Routers. Unsigned script within the ISO image is not verified during system upgrade before it is executed. A local user can execute unsigned code during the boot process on an affected device.
MitigationInstall updates from vendor's website.
Vulnerable software versionsCisco 8000 Series Routers: before 7.0.12.23i.BASE
Cisco Network Convergence System 5000 Series: before 7.0.12.23i.BASE
CPE2.3- cpe:2.3:h:cisco_systems:cisco_8000_series_routers:*:*:*:*:*:*:*:*
- cpe:2.3:h:cisco_systems:cisco_network_convergence_system_5000_series:*:*:*:*:*:*:*:*
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ioxr-l-zNhcGCBt
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvs70887
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.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.
The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Improper Verification of Cryptographic Signature
EUVDB-ID: #VU50380
Risk: Low
CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2021-1244
CWE-ID:
CWE-347 - Improper Verification of Cryptographic Signature
Exploit availability: No
DescriptionThe vulnerability allows a local user to bypass implemented security restrictions.
Multiple vulnerabilities in Cisco Network Convergence System (NCS) 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for the Cisco 8000 Series Routers due to an unlocked version of GRUB boot loader on an affected device. Unsigned script within the ISO image is not verified during system upgrade before it is executed. A local user can modifying the boot process from the GRUB menu and bypass the boot chain of trust.
MitigationInstall updates from vendor's website.
Vulnerable software versionsCisco Network Convergence System 5000 Series: before 3
Cisco 8000 Series Routers: before 3
Cisco ASR 9000 Series Aggregation Services Routers: before 3
CPE2.3- cpe:2.3:h:cisco_systems:cisco_network_convergence_system_5000_series:*:*:*:*:*:*:*:*
- cpe:2.3:h:cisco_systems:cisco_8000_series_routers:*:*:*:*:*:*:*:*
- cpe:2.3:h:cisco_systems:cisco_asr_9000_series_aggregation_services_routers:*:*:*:*:*:*:*:*
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ioxr-l-zNhcGCBt
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvr07463
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.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected device in order to exploit this vulnerability.
The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
