CVE-2021-34749

NameCVE-2021-34749
DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3317-1, DSA-5354-1
Debian Bugs1021276

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
snort (PTS)buster2.9.7.0-5vulnerable
buster (security)2.9.20-0+deb10u1fixed
bullseye2.9.15.1-5vulnerable
bullseye (security)2.9.20-0+deb11u1fixed
sid2.9.15.1-6vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
snortsourcebuster2.9.20-0+deb10u1DLA-3317-1
snortsourcebullseye2.9.20-0+deb11u1DSA-5354-1
snortsource(unstable)(unfixed)1021276

Notes

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sni-data-exfil-mFgzXqLN

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