CVE-2021-34793— Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Transparent Mode Denial of Service Vulnerability
Quick assessment
Affected
Cisco Cisco Adaptive Security Appliance (ASA) Software
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
Cisco Firepower Threat Defense（FTD）是美国思科（Cisco）公司的一套提供下一代防火墙服务的统一软件。 Cisco Firepower Threat Defense（FTD）和Cisco Adaptive Security Appliances Software（ASA Software） 存在安全漏洞，该漏洞源于受影响设备在透明模式下运行时，某些TCP段处理错误造成的。攻击者可利用该漏洞毒害MAC地址表，从而导致拒绝服务(DoS)漏洞。
Possible ATT&CK Techniques 2 AI
T1499.004 · Application or System Exploitation T1498.002 · Reflection Amplification
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I. Basic Information for CVE-2021-34793
Vulnerability Information
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Vulnerability Title
Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Transparent Mode Denial of Service Vulnerability
Source: CVE Program / CVE List V5
Vulnerability Description
A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
通信信道中传输过程中消息完整性的不正确执行
Source: CVE Program / CVE List V5
Vulnerability Title
Cisco Firepower Threat Defense（FTD）和Cisco Adaptive Security Appliances Software（ASA Software） 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cisco Firepower Threat Defense（FTD）是美国思科（Cisco）公司的一套提供下一代防火墙服务的统一软件。 Cisco Firepower Threat Defense（FTD）和Cisco Adaptive Security Appliances Software（ASA Software） 存在安全漏洞，该漏洞源于受影响设备在透明模式下运行时，某些TCP段处理错误造成的。攻击者可利用该漏洞毒害MAC地址表，从而导致拒绝服务(DoS)漏洞。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Cisco | Cisco Adaptive Security Appliance (ASA) Software | n/a | - |
|
II. Public POCs for CVE-2021-34793
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2021-34793 (1)
-
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-dos-JxYWMJyL vendor-advisory x_refsource_CISCO
Same Patch Batch · Cisco · 2021-10-27 · 20 CVEs total
| CVE-2021-40117 | 8.6 HIGH | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SSL/TLS D |
| CVE-2021-34781 | 8.6 HIGH | Cisco Firepower Threat Defense Software SSH Connections Denial of Service Vulnerability |
| CVE-2021-34783 | 8.6 HIGH | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Software- |
| CVE-2021-34792 | 8.6 HIGH | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Resource |
| CVE-2021-40116 | 8.6 HIGH | Multiple Cisco Products Snort Rule Denial of Service Vulnerability |
| CVE-2021-40118 | 8.6 HIGH | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Servi |
| CVE-2021-34762 | 8.1 HIGH | Cisco Firepower Management Center Software Authenticated Directory Traversal Vulnerability |
| CVE-2021-40114 | 6.8 MEDIUM | Multiple Cisco Products Snort Memory Leak Denial of Service Vulnerability |
| CVE-2021-34756 | 6.7 MEDIUM | Cisco Firepower Threat Defense Software Command Injection Vulnerabilities |
| CVE-2021-34755 | 6.7 MEDIUM | Cisco Firepower Threat Defense Software Command Injection Vulnerabilities |
| CVE-2021-34754 | 5.8 MEDIUM | Cisco Firepower Threat Defense Software Ethernet Industrial Protocol Policy Bypass Vulnera |
| CVE-2021-34794 | 5.3 MEDIUM | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software SNMP Acce |
| CVE-2021-34787 | 5.3 MEDIUM | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Identity- |
| CVE-2021-40125 | 5.3 MEDIUM | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IKEv2 Sit |
| CVE-2021-34764 | 4.8 MEDIUM | Cisco Firepower Management Center Software Cross-Site Scripting and Open Redirect Vulnerab |
| CVE-2021-34763 | 4.8 MEDIUM | Cisco Firepower Management Center Software Cross-Site Scripting and Open Redirect Vulnerab |
| CVE-2021-34791 | 4.7 MEDIUM | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Applicati |
| CVE-2021-34790 | 4.7 MEDIUM | Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Applicati |
| CVE-2021-34761 | 4.4 MEDIUM | Cisco Firepower Threat Defense Software CLI Arbitrary File Write Vulnerability |
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V. Comments for CVE-2021-34793
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