A vulnerability in the telnetd process of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a reload of the affected service. The vulnerability is due to improper processing of malformed Telnet packets directed to a device configured to process such packets. An attacker could exploit this vulnerability by sending a malformed Telnet packet to a device that is configured to accept Telnet connections to itself and process them for remote management. An exploit could allow the attacker to cause a reload of the affected service. Cisco has confirmed the vulnerability and released software updates. To exploit this vulnerability, the attacker must be able to send malformed Telnet packets to the targeted device, making exploitation more difficult in environments that restrict network access from untrusted sources. In addition, an attacker may need to acquire additional information about the device such as whether the device is configured to accept Telnet connections for remote management. This condition must be met for a successful exploit. Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
| Version | Description | Section | Status | Date |
| 1.0 | Initial Release | NA | Final | 2015-Jun-10 |
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