Cisco Security Advisory
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CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:X/RL:X/RC:X
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A vulnerability in the endpoint software of Cisco AMP for Endpoints and Clam AntiVirus could allow an authenticated, local attacker to cause the running software to delete arbitrary files on the system.
The vulnerability is due to a race condition that could occur when scanning malicious files. An attacker with local shell access could exploit this vulnerability by executing a script that could trigger the race condition. A successful exploit could allow the attacker to delete arbitrary files on the system that the attacker would not normally have privileges to delete, producing system instability or causing the endpoint software to stop working.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-famp-ZEpdXy
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Vulnerable Products
At the time of publication, this vulnerability affected the following products prior to the first fixed release:
- Cisco AMP for Endpoints (MacOS and Linux)
- ClamAV
This vulnerability cannot be exploited on endpoints that are using Audit Policy Mode.
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
Impact on Cisco AMP for Endpoints (Windows)
Cisco bug ID CSCvt98752 has been raised to investigate the full impact on the Windows Connector of the proof-of-concept exploit code for this vulnerability. The methods described in the RACK911 publication (described in Source) cannot be used to force the Windows Connector to quarantine files that are loaded into a process or as a process. However, they can impact supporting files that are necessary for the continued operation of the Connector. The team is investigating potential solutions to address this issue.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
- Email Security Appliances (ESA)
- Web Security Appliances (WSA)
- Immunet
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Cisco AMP for Endpoints contains a feature known as guardrails to prevent accidentally blocking or quarantining legitimate applications and operating system components. This vulnerability involves a tight race condition in which the guardrails feature could be bypassed.
Although Cisco ESA and Cisco WSA are not affected, they can be used to integrate with third-party antivirus engines. Those engines should be upgraded to a fixed version of software by the corresponding antivirus provider.
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There are no workarounds that address this vulnerability.
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When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Fixed Releases
At the time of publication, this vulnerability was fixed in the following versions (and later):
- Cisco AMP for Endpoints - Linux version 1.12.4
- Cisco AMP for Endpoints - MacOS version 1.12.4
- ClamAV version 0.103 and 0.102.4
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
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This vulnerability was discovered when reviewing a publication by RACK911 on exploiting antivirus by using directory junctions and symlinks.
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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.
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Show LessVersion Description Section Status Date 1.0 Initial public release. — Final 2020-JUN-17
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