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5.3
MEDIUM CVSS 3.1
CVE-2021-1236
Cisco Snort Detection Engine Policy Bypass Vulnerability
Description

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.

INFO

Published Date :

Jan. 13, 2021, 10:15 p.m.

Last Modified :

Nov. 26, 2024, 4:09 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2021-1236 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco ios_xe
2 Cisco firepower_management_center
3 Cisco firepower_threat_defense
4 Cisco 1100-4p_integrated_services_router
5 Cisco 1100-8p_integrated_services_router
6 Cisco 1101-4p_integrated_services_router
7 Cisco 1109-2p_integrated_services_router
8 Cisco 1109-4p_integrated_services_router
9 Cisco 1111x-8p_integrated_services_router
10 Cisco 4221_integrated_services_router
11 Cisco 4321_integrated_services_router
12 Cisco 4331_integrated_services_router
13 Cisco 4351_integrated_services_router
14 Cisco 4431_integrated_services_router
15 Cisco 4451-x_integrated_services_router
16 Cisco 4461_integrated_services_router
17 Cisco secure_firewall_management_center
18 Cisco isa_3000
19 Cisco csr_1000v
1 Snort snort
: Total Affected Vendor : 2 | Products : 20
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 MEDIUM [email protected]
CVSS 3.0 MEDIUM [email protected]
CVSS 3.1 MEDIUM [email protected]
Solution
A vulnerability in the Snort detection engine could allow an attacker to bypass configured policies.
  • Upgrade to a fixed version of the affected product.
  • Upgrade the Snort packages.
Public PoC/Exploit Available at Github

CVE-2021-1236 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-1236.

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

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-1236 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-1236 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
n0-traces/cve_monitor

Automatic monitor github cve using Github Actions

Python

Updated: 5 months, 4 weeks ago
2 stars 55 fork 55 watcher
Born at : April 7, 2021, 11:16 a.m. This repo has been linked 1008 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-1236 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-1236 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CPE Deprecation Remap by [email protected]

    Nov. 26, 2024

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.17:*:*:*:*:*:*:* OR *cpe:2.3:a:cisco:secure_firewall_management_center:2.9.17:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Nov. 26, 2024

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.14.14:*:*:*:*:*:*:* OR *cpe:2.3:a:cisco:secure_firewall_management_center:2.9.14.14:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Nov. 26, 2024

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.14.0:*:*:*:*:*:*:* OR *cpe:2.3:a:cisco:secure_firewall_management_center:2.9.14.0:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Nov. 26, 2024

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.15:*:*:*:*:*:*:* OR *cpe:2.3:a:cisco:secure_firewall_management_center:2.9.15:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    Nov. 26, 2024

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.16:*:*:*:*:*:*:* OR *cpe:2.3:a:cisco:secure_firewall_management_center:2.9.16:*:*:*:*:*:*:*
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html
    Added Reference https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq
    Added Reference https://www.debian.org/security/2023/dsa-5354
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1100-4p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1100-4p_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1101-4p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1101-4p_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1109-2p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1109-2p_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4431:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4431_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4461:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4461_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4451-x:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4451-x_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1109-4p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1109-4p_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4221:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4221_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4331:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4331_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4321:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4321_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_4351:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:4351_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1111x-8p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1111x-8p_integrated_services_router:-:*:*:*:*:*:*:*
  • CPE Deprecation Remap by [email protected]

    May. 22, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:h:cisco:isr_1100-8p:-:*:*:*:*:*:*:* OR *cpe:2.3:h:cisco:1100-8p_integrated_services_router:-:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Feb. 19, 2023

    Action Type Old Value New Value
    Added Reference https://www.debian.org/security/2023/dsa-5354 [No Types Assigned]
  • CVE Modified by [email protected]

    Feb. 11, 2023

    Action Type Old Value New Value
    Added Reference https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html [No Types Assigned]
  • Initial Analysis by [email protected]

    Jan. 19, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:P/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
    Changed Reference Type https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq No Types Assigned https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq Vendor Advisory
    Added CWE NIST CWE-670
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:* versions up to (excluding) 17.4.1 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:-:*:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:a:cisco:firepower_management_center:2.9.14.0:*:*:*:*:*:*:* *cpe:2.3:a:cisco:firepower_management_center:2.9.14.14:*:*:*:*:*:*:* *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_threat_defense:*:*:*:*:*:*:*:* versions up to (excluding) 6.5.0.5
    Added CPE Configuration OR *cpe:2.3:a:snort:snort:*:*:*:*:*:*:*:* versions up to (excluding) 2.9.14
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.3
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 4
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 5
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.27 }} -0.09%

score

0.50608

percentile