CVE-2021-34749: Multiple Cisco Products Server Name Identification Data Exfiltration Vulnerability
First published: Wed Aug 18 2021(Updated: )
A vulnerability in Server Name Identification (SNI) request filtering of Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD), and the Snort detection engine could allow an unauthenticated, remote attacker to bypass filtering technology on an affected device and exfiltrate data from a compromised host. This vulnerability is due to inadequate filtering of the SSL handshake. An attacker could exploit this vulnerability by using data from the SSL client hello packet to communicate with an external server. A successful exploit could allow the attacker to execute a command-and-control attack on a compromised host and perform additional data exfiltration attacks.
Credit: ykramarz@cisco.com ykramarz@cisco.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/snort | <=2.9.7.0-5<=2.9.15.1-5<=2.9.15.1-6 | 2.9.20-0+deb10u1 2.9.20-0+deb11u1 |
| Cisco Firepower Management Center | =2.9.18 | |
| Cisco IronPort Web Security Appliance | =14.5 | |
| Cisco Firepower Management Center Virtual Appliance Firmware | =6.6.0 | |
| Cisco Firepower Management Center Virtual Appliance Firmware | =6.7.0 | |
| Cisco Firepower Management Center Virtual Appliance Firmware | =7.0.0 | |
| Cisco Firepower Management Center Virtual Appliance Firmware | =7.1.0 | |
| Cisco Secure Firewall Management Center | =2.9.18 |
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Reference Links
Frequently Asked Questions
What is CVE-2021-34749?
CVE-2021-34749 is a vulnerability in Server Name Identification (SNI) request filtering of Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD), and the Snort detection engine.
How severe is CVE-2021-34749?
CVE-2021-34749 has a severity score of 8.6 (high).
Which software is affected by CVE-2021-34749?
CVE-2021-34749 affects Cisco Web Security Appliance (WSA), Cisco Firepower Threat Defense (FTD), and the Snort detection engine.
How can an attacker exploit CVE-2021-34749?
An unauthenticated, remote attacker can exploit CVE-2021-34749 to bypass filtering technology on an affected device and exfiltrate data.
Where can I find more information about CVE-2021-34749?
You can find more information about CVE-2021-34749 at the following references: [1](https://lists.debian.org/debian-lts-announce/2023/02/msg00011.html) [2](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sni-data-exfil-mFgzXqLN) [3](https://www.debian.org/security/2023/dsa-5354)
- collector/security-tracker-debian
- collector/nvd-index
- agent/references
- agent/type
- agent/title
- agent/weakness
- agent/remedy
- agent/description
- agent/first-publish-date
- collector/mitre-cve
- source/MITRE
- collector/nvd-api
- source/NVD
- agent/software-canonical-lookup
- agent/last-modified-date
- agent/author
- agent/severity
- agent/softwarecombine
- agent/tags
- agent/event
- package-manager/debian
- vendor/cisco
- canonical/cisco firepower management center
- version/cisco firepower management center/2.9.18
- canonical/cisco ironport web security appliance
- version/cisco ironport web security appliance/14.5
- canonical/cisco firepower management center virtual appliance firmware
- version/cisco firepower management center virtual appliance firmware/6.6.0
- version/cisco firepower management center virtual appliance firmware/6.7.0
- version/cisco firepower management center virtual appliance firmware/7.0.0
- version/cisco firepower management center virtual appliance firmware/7.1.0
- canonical/cisco secure firewall management center
- version/cisco secure firewall management center/2.9.18