8.6
HIGH
CVE-2021-34783
"Cisco ASA/FTD SSL/TLS Denial of Service Vulnerability"
Description

A vulnerability in the software-based SSL/TLS message handler of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to insufficient validation of SSL/TLS messages when the device performs software-based SSL/TLS decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Datagram TLS (DTLS) messages cannot be used to exploit this vulnerability.

INFO

Published Date :

Oct. 27, 2021, 7:15 p.m.

Last Modified :

Nov. 21, 2024, 6:11 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

4.0

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2021-34783 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 adaptive_security_appliance_software
2 Cisco firepower_threat_defense
3 Cisco asa_5585-x_firmware
4 Cisco asa_5512-x_firmware
5 Cisco asa_5515-x_firmware
6 Cisco asa_5505_firmware
7 Cisco asa_5525-x_firmware
8 Cisco asa_5545-x_firmware
9 Cisco asa_5555-x_firmware
10 Cisco asa_5580_firmware
11 Cisco asa_5580
12 Cisco asa_5505
13 Cisco asa_5585-x
14 Cisco asa_5512-x
15 Cisco asa_5515-x
16 Cisco asa_5525-x
17 Cisco asa_5545-x
18 Cisco asa_5555-x
: Total Affected Vendor : 1 | Products : 18
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-2021-34783.

URL Resource
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-decrypt-dos-BMxYjm8M Vendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-decrypt-dos-BMxYjm8M Vendor Advisory

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).

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

The following list is the news that have been mention CVE-2021-34783 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-34783 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.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-decrypt-dos-BMxYjm8M
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Removed CVSS V3 Cisco Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
    Added CVSS V3.1 Cisco Systems, Inc. AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
  • CPE Deprecation Remap by [email protected]

    Aug. 16, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.14.0 from (excluding) 9.14.3.9 OR *cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* versions from (including) 9.14.0 from (excluding) 9.14.3.9
  • CPE Deprecation Remap by [email protected]

    Aug. 16, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.12.0 from (excluding) 9.12.4.29 OR *cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* versions from (including) 9.12.0 from (excluding) 9.12.4.29
  • CPE Deprecation Remap by [email protected]

    Aug. 16, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.8.0 from (excluding) 9.8.4.40 OR *cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* versions from (including) 9.8.0 from (excluding) 9.8.4.40
  • CPE Deprecation Remap by [email protected]

    Aug. 16, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.15.0 from (excluding) 9.15.1.17 OR *cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* versions from (including) 9.15.0 from (excluding) 9.15.1.17
  • CPE Deprecation Remap by [email protected]

    Aug. 16, 2023

    Action Type Old Value New Value
    Changed CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.16.0 from (excluding) 9.16.2 OR *cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* versions from (including) 9.16.0 from (excluding) 9.16.2
  • Initial Analysis by [email protected]

    Oct. 29, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:C)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Changed Reference Type https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-decrypt-dos-BMxYjm8M No Types Assigned https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-tls-decrypt-dos-BMxYjm8M Vendor Advisory
    Added CWE NIST CWE-20
    Added CPE Configuration OR *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.8.0 up to (excluding) 9.8.4.40 *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.12.0 up to (excluding) 9.12.4.29 *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.14.0 up to (excluding) 9.14.3.9 *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.15.0 up to (excluding) 9.15.1.17 *cpe:2.3:a:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* versions from (including) 9.16.0 up to (excluding) 9.16.2 *cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* versions from (including) 6.4.0 up to (excluding) 6.4.0.13 *cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* versions from (including) 6.6.0 up to (excluding) 6.6.5 *cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* versions from (including) 6.7.0 up to (excluding) 6.7.0.3 *cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:* versions from (including) 7.0.0 up to (excluding) 7.0.1
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5512-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5512-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5512-x:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5505_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5505_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5505:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5515-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5515-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5515-x:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5525-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5525-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5525-x:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5545-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5545-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5545-x:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5555-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5555-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5555-x:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5580_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5580_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5580:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:asa_5585-x_firmware:009.016\(001\):*:*:*:*:*:*:* *cpe:2.3:o:cisco:asa_5585-x_firmware:009.016\(001.025\):*:*:*:*:*:*:* OR cpe:2.3:h:cisco:asa_5585-x:-:*:*:*:*:*:*:*
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.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-34783 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-2021-34783 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client CAPEC-23: File Content Injection File Content Injection CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-31: Accessing/Intercepting/Modifying HTTP Cookies Accessing/Intercepting/Modifying HTTP Cookies CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-63: Cross-Site Scripting (XSS) Cross-Site Scripting (XSS) CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-73: User-Controlled Filename User-Controlled Filename CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-81: Web Server Logs Tampering Web Server Logs Tampering CAPEC-83: XPath Injection XPath Injection CAPEC-85: AJAX Footprinting AJAX Footprinting CAPEC-88: OS Command Injection OS Command Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-109: Object Relational Mapping Injection Object Relational Mapping Injection CAPEC-110: SQL Injection through SOAP Parameter Tampering SQL Injection through SOAP Parameter Tampering CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-136: LDAP Injection LDAP Injection CAPEC-153: Input Data Manipulation Input Data Manipulation CAPEC-182: Flash Injection Flash Injection CAPEC-209: XSS Using MIME Type Mismatch XSS Using MIME Type Mismatch CAPEC-230: Serialized Data with Nested Payloads Serialized Data with Nested Payloads CAPEC-231: Oversized Serialized Data Payloads Oversized Serialized Data Payloads CAPEC-250: XML Injection XML Injection CAPEC-261: Fuzzing for garnering other adjacent user/sensitive data Fuzzing for garnering other adjacent user/sensitive data CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-473: Signature Spoof Signature Spoof CAPEC-588: DOM-Based XSS DOM-Based XSS CAPEC-664: Server Side Request Forgery Server Side Request Forgery CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-100: Overflow Buffers Overflow Buffers CAPEC-123: Buffer Manipulation Buffer Manipulation
Exploit Prediction

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

0.16 }} 0.02%

score

0.52805

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: