CVE-2021-1236

Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network.

CVSS v3.0 5.3 MEDIUM
CVSS v2.0 5.0 MEDIUM

5.3^/10

CVSS v3.0 : MEDIUM

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

5.0^/10

CVSS v2.0 : MEDIUM

V2 Legend

Vector : AV:N/AC:L/Au:N/C:N/I:P/A:N

Exploitability : 10.0 / Impact : 2.9

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact NONE

Integrity Impact PARTIAL

Availability Impact NONE

References

Link	Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq	Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html
https://www.debian.org/security/2023/dsa-5354

Configurations

Configuration 1 (hide)

AND

cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*

OR	cpe:2.3:h:cisco:csr_1000v:-:::::::*
	cpe:2.3:h:cisco:isa_3000:-:::::::*
	cpe:2.3:h:cisco:isr_1100-4p:-:::::::*
	cpe:2.3:h:cisco:isr_1100-8p:-:::::::*
	cpe:2.3:h:cisco:isr_1101-4p:-:::::::*
	cpe:2.3:h:cisco:isr_1109-2p:-:::::::*
	cpe:2.3:h:cisco:isr_1109-4p:-:::::::*
	cpe:2.3:h:cisco:isr_1111x-8p:-:::::::*
	cpe:2.3:h:cisco:isr_4221:-:::::::*
	cpe:2.3:h:cisco:isr_4321:-:::::::*
	cpe:2.3:h:cisco:isr_4331:-:::::::*
	cpe:2.3:h:cisco:isr_4351:-:::::::*
	cpe:2.3:h:cisco:isr_4431:-:::::::*
	cpe:2.3:h:cisco:isr_4451-x:-:::::::*
	cpe:2.3:h:cisco:isr_4461:-:::::::*

Configuration 2 (hide)

OR	cpe:2.3:a:cisco:firepower_management_center:2.9.14.0:::::::*
	cpe:2.3:a:cisco:firepower_management_center:2.9.15:::::::*
	cpe:2.3:a:cisco:firepower_management_center:2.9.16:::::::*
	cpe:2.3:a:cisco:firepower_management_center:2.9.17:::::::*
	cpe:2.3:a:cisco:firepower_management_center:2.9.14.14:::::::*
	cpe:2.3:a:cisco:firepower_threat_defense::::::::

Configuration 3 (hide)

cpe:2.3:a:snort:snort:*:*:*:*:*:*:*:*

Information

Published : 2021-01-13 14:15

Updated : 2023-02-18 20:15

NVD link : CVE-2021-1236

Mitre link : CVE-2021-1236

JSON object : View

CWE

CWE-670

Always-Incorrect Control Flow Implementation

Products Affected

cisco

isr_1111x-8p
isr_4431
isr_1100-8p
isr_4221
firepower_management_center
isr_4351
isr_1109-4p
ios_xe
isa_3000
isr_1101-4p
isr_4321
firepower_threat_defense
isr_1100-4p
csr_1000v
isr_4331
isr_4461
isr_1109-2p
isr_4451-x

snort

snort

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq", "name": "20210113 Multiple Cisco Products Snort Application Detection Engine Policy Bypass Vulnerability", "tags": ["Vendor Advisory"], "refsource": "CISCO"}, {"url": "https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html", "name": "[debian-lts-announce] 20230210 [SECURITY] [DLA 3317-1] snort security update", "tags": [], "refsource": "MLIST"}, {"url": "https://www.debian.org/security/2023/dsa-5354", "name": "DSA-5354", "tags": [], "refsource": "DEBIAN"}]}, "data_format": "MITRE", "description": {"description_data": [{"lang": "en", "value": "Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-670"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2021-1236", "ASSIGNER": "psirt@cisco.com"}}, "impact": {"baseMetricV2": {"cvssV2": {"version": "2.0", "baseScore": 5.0, "accessVector": "NETWORK", "vectorString": "AV:N/AC:L/Au:N/C:N/I:P/A:N", "authentication": "NONE", "integrityImpact": "PARTIAL", "accessComplexity": "LOW", "availabilityImpact": "NONE", "confidentialityImpact": "NONE"}, "severity": "MEDIUM", "acInsufInfo": false, "impactScore": 2.9, "obtainAllPrivilege": false, "exploitabilityScore": 10.0, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}, "baseMetricV3": {"cvssV3": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}}, "publishedDate": "2021-01-13T22:15Z", "configurations": {"nodes": [{"children": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "17.4.1"}]}, {"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:h:cisco:csr_1000v:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isa_3000:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1100-4p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1100-8p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1101-4p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1109-2p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1109-4p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_1111x-8p:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4221:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4321:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4331:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4351:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4431:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4451-x:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}, {"cpe23Uri": "cpe:2.3:h:cisco:isr_4461:-:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": false}]}], "operator": "AND", "cpe_match": []}, {"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:a:cisco:firepower_management_center:2.9.14.0:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:a:cisco:firepower_management_center:2.9.15:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:a:cisco:firepower_management_center:2.9.16:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:a:cisco:firepower_management_center:2.9.17:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:a:cisco:firepower_management_center:2.9.14.14:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "6.5.0.5"}]}, {"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:a:snort:snort:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "2.9.14"}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2023-02-19T04:15Z"}

5.3 /10

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact LOW

Availability Impact NONE

Scope UNCHANGED

5.0 /10

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact NONE

Integrity Impact PARTIAL

Availability Impact NONE

JSON object

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