Vulnerability · Published Sep 23, 2021 · Assigned by cisco
CVE-2021-34705Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability
Medium 5.3
In plain English
A medium-severity security flaw in Cisco IOS from Cisco. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 63% of all known vulnerabilities).
Official 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.
Affected products (as reported)
Weakness: CWE-232 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- 20210922 Cisco IOS and IOS XE Software FXO Interface Destination Pattern Bypass Vulnerability vendor-advisory, x_refsource_CISCO