A vulnerability in file descriptor handling of the Cisco Email Security Appliance (ESA) could allow an authenticated, remote attacker to cause a denial of service (DoS) condition due to the affected device unexpectedly reloading. The vulnerability is due to failure to release file descriptors when the requested file action is completed. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to cause a DoS condition due to the affected device failing to release file descriptors. When all file descriptors are in use, the device can reload unexpectedly. Cisco has confirmed the vulnerability; however, software updates are not available. To exploit this vulnerability, an attacker must authenticate to the targeted device. This access requirement reduces the likelihood of 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-Sep-30 |
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