CVE-2017-12353: A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could ...

Description

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device. The vulnerability is due to improper error handling of a malformed MIME header in an email attachment. An attacker could exploit this vulnerability by sending an email with a crafted MIME attachment. For example, a successful exploit could allow the attacker to bypass configured user filters to drop the email. The malformed MIME headers may not be RFC compliant. However, some mail clients could still allow users to access the attachment, which may not have been properly filtered by the device. Cisco Bug IDs: CSCvf44666.

Metrics

EPSS Probability

1.64%

73.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-254

Affected Software

Vendor	Product	Versions
Cisco	Asyncos	All versions

References

http://www.securityfocus.com/bid/102002Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1039917Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171129-esaVendor Advisory
http://www.securityfocus.com/bid/102002Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1039917Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171129-esaVendor Advisory

Timeline

Published: Nov 30, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-12353?

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device. The vulnerability is due to improper error handling of a malformed MIME header in an email attachment. An attacker could exploit this vulnerability by sending an email with a crafted MIME attachment. For example, a successful exploit could allow the attacker to bypass configured user filters to drop the email. The malformed MIME headers may not be RFC compliant. However, some mail clients could still allow users to access the attachment, which may not have been properly filtered by the device. Cisco Bug IDs: CSCvf44666.

How severe is CVE-2017-12353?

Severity scoring for CVE-2017-12353 is pending analysis. The EPSS model estimates a 1.64% probability of exploitation in the next 30 days.

How do I fix CVE-2017-12353?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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