A vulnerability has been found in Cisco IOS XE on ASR 920 (Router Operating System) (affected version unknown) and classified as problematic. This vulnerability affects an unknown functionality of the component USB Modem. The manipulation with an unknown input leads to a input validation vulnerability (File). The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect integrity, and availability. CVE summarizes:

A vulnerability in the USB-modem code of Cisco IOS XE Software running on Cisco ASR 920 Series Aggregation Services Routers could allow an authenticated, local attacker to overwrite arbitrary files on the underlying operating system of an affected device. The vulnerability is due to improper input validation of the platform usb modem command in the CLI of the affected software. An attacker could exploit this vulnerability by modifying the platform usb modem command in the CLI of an affected device. A successful exploit could allow the attacker to overwrite arbitrary files on the underlying operating system of an affected device. Cisco Bug IDs: CSCvf10783.

The bug was discovered 09/06/2017. The weakness was published 09/07/2017 as cisco-sa-20170906-asr920-2 as confirmed advisory (Website). The advisory is shared for download at tools.cisco.com. This vulnerability was named CVE-2017-6795 since 03/09/2017. The attack needs to be approached locally. The successful exploitation needs a single authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 01/11/2021).

The vulnerability was handled as a non-public zero-day exploit for at least 1 days. During that time the estimated underground price was around $5k-$25k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 316164 (Cisco IOS XE Software for Cisco ASR 920 Series Routers Arbitrary File Overwrite Vulnerability (cisco-sa-20170906-asr920-2)).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Similar entry is available at 106241.

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Type

• Router Operating System

Vendor

• Cisco

Name

• IOS XE

License

• commercial

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