STIGUI
V-256670CAT II — Medium severitySV-256670r961863_rule

VAMI must disable client-initiated Transport Layer Security (TLS) renegotiation.

Rule version VCLD-70-000026 · STIG v1 · 2026-08-31

Discussion

All versions of the Secure Sockets Layer (SSL) and TLS protocols (up to and including TLS 1.2) are vulnerable to a man-in-the-middle attack (CVE-2009-3555) during a renegotiation. This vulnerability allows an attacker to "prefix" a chosen plaintext to the HTTP request as seen by the web server. The protocols have since been amended by RFC 5746, but the fix must be supported by both client and server to be effective.

While Lighttpd and the underlying OpenSSL libraries are no longer vulnerable, steps must be taken to account for older clients that do not support RFC 5746. To this end, Lighttpd disables client-initiated renegotiation entirely by default. This configuration must be validated and maintained.

Check

At the command prompt, run the following command:

# /opt/vmware/sbin/vami-lighttpd -p -f /opt/vmware/etc/lighttpd/lighttpd.conf 2>/dev/null|grep "ssl\.disable-client-renegotiation"|sed 's: ::g'

If no line is returned, this is not a finding.

If "ssl.disable-client-renegotiation" is set to "disabled", this is a finding.

Note: The command must be run from a bash shell and not from a shell generated by the "appliance shell". Use the "chsh" command to change the shell for the account to "/bin/bash". Refer to KB Article 2100508 for more details:

https://kb.vmware.com/s/article/2100508

Fix

Navigate to and open:

/opt/vmware/etc/lighttpd/lighttpd.conf

Remove any setting for "ssl.disable-client-renegotiation".

Restart the service with the following command:

# vmon-cli --restart applmgmt

Identifiers

Group ID
V-256670
Group title
SRG-APP-000516-WSR-000174
Rule ID
SV-256670r961863_rule
Check ID
C-60345r888530_chk
Fix ID
F-60288r888531_fix