Cisco Security Advisory
Click Icon to Copy Verbose Score
AV:N/AC:L/Au:N/C:N/I:N/A:P/E:F/RL:OF/RC:C
-
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.
-
Cisco has released bug ID CSCuq31566 for registered users, which contains additional details and an up-to-date list of affected product versions.
Vulnerable Products
At the time this alert was first published, Cisco Network Convergence System 6000 Series Routers running Cisco IOS XR Software release 5.0.1 was vulnerable. Later releases of Cisco IOS XR Software may also be vulnerable.Products Confirmed Not Vulnerable
No other Cisco products are currently known to be affected by these vulnerabilities.
-
Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Administrators can help protect affected systems from external attacks by using a solid firewall strategy.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
-
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via email at tac@cisco.com.
-
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.
-
Show LessVersion Description Section Status Date 1.0 Initial Release NA Final 2015-Jun-10
-
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.