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CVE-2021-34705— Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability

Quick assessment

Affected
Cisco Cisco IOS
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 IOS和Cisco IOS XE Software都是美国思科（Cisco）公司的产品。Cisco IOS是一套为其网络设备开发的操作系统。Cisco IOS XE Software是一个操作系统。用于企业有线和无线访问，汇聚，核心和WAN的单一操作系统，Cisco IOS XE降低了业务和网络的复杂性。 Cisco IOS 和 IOS XE Software 存在安全漏洞，该漏洞源于由于对外汇局 (FXO) 接口上的拨号字符串验证不足。该漏洞可能允许未经身份验证的远程攻击者绕过配置的目标模式

CVSS 5.3 · Medium EPSS 1.01% · P62

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2021-34705

Vulnerability Information
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Vulnerability Title
Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability
Source: CVE Program / CVE List V5
Vulnerability Description
A vulnerability in the Voice Telephony Service Provider (VTSP) service of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured destination patterns and dial arbitrary numbers. This vulnerability is due to insufficient validation of dial strings at Foreign Exchange Office (FXO) interfaces. An attacker could exploit this vulnerability by sending a malformed dial string to an affected device via either the ISDN protocol or SIP. A successful exploit could allow the attacker to conduct toll fraud, resulting in unexpected financial impact to affected customers.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
未定义值处理不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Cisco IOS和Cisco IOS XE Software 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cisco IOS和Cisco IOS XE Software都是美国思科（Cisco）公司的产品。Cisco IOS是一套为其网络设备开发的操作系统。Cisco IOS XE Software是一个操作系统。用于企业有线和无线访问，汇聚，核心和WAN的单一操作系统，Cisco IOS XE降低了业务和网络的复杂性。 Cisco IOS 和 IOS XE Software 存在安全漏洞，该漏洞源于由于对外汇局 (FXO) 接口上的拨号字符串验证不足。该漏洞可能允许未经身份验证的远程攻击者绕过配置的目标模式
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 IOS n/a -

II. Public POCs for CVE-2021-34705

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III. Intelligence Information for CVE-2021-34705

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Same Patch Batch · Cisco · 2021-09-23 · 33 CVEs total

CVE-2021-34770 10.0 CRITICAL Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Exe
CVE-2021-1619 9.8 CRITICAL Cisco IOS XE Software NETCONF and RESTCONF Authentication Bypass Vulnerability
CVE-2021-34727 9.8 CRITICAL Cisco IOS XE SD-WAN Software Buffer Overflow Vulnerability
CVE-2021-1624 8.6 HIGH Cisco IOS XE Software Rate Limiting Network Address Translation Denial of Service Vulnerab
CVE-2021-1622 8.6 HIGH Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Common Open Policy Servi
CVE-2021-1615 8.6 HIGH Cisco Embedded Wireless Controller Software for Catalyst Access Points Denial of Service V
CVE-2021-1611 8.6 HIGH Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers EoGRE Denial of Servic
CVE-2021-1565 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-34769 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-34768 8.6 HIGH Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Denial of Servi
CVE-2021-1419 7.8 HIGH Cisco Access Points SSH Management Privilege Escalation Vulnerability
CVE-2021-1623 7.7 HIGH Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Simple Network Managemen
CVE-2021-1620 7.7 HIGH Cisco IOS and IOS XE Software IKEv2 AutoReconnect Feature Denial of Service Vulnerability
CVE-2021-34699 7.7 HIGH Cisco IOS and IOS XE Software TrustSec CLI Parser Denial of Service Vulnerability
CVE-2021-1621 7.4 HIGH Cisco IOS XE Software Interface Queue Wedge Denial of Service Vulnerability
CVE-2021-34767 7.4 HIGH Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers IPv6 Denial of Service
CVE-2021-34740 7.4 HIGH Cisco Aironet Access Points WLAN Control Protocol Packet Buffer Leak Denial of Service Vul
CVE-2021-34714 7.4 HIGH Multiple Cisco Operating Systems Unidirectional Link Detection Denial of Service Vulnerabi
CVE-2021-34703 6.8 MEDIUM Cisco IOS and IOS XE Software Link Layer Discovery Protocol Denial of Service Vulnerabilit
CVE-2021-34729 6.7 MEDIUM Cisco IOS XE SD-WAN Software Command Injection Vulnerability

Showing top 20 of 33 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Cisco IOS
Same vendor: Cisco
Same weakness: CWE-232

V. Comments for CVE-2021-34705

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