Apache HTTP Server
TMA-APACHE-7.5
Ensure Weak SSL/TLS Ciphers Are Disabled
Description
Disable weak SSL ciphers using the SSLCipherSuite, and SSLHonorCipherOrder directives. The SSLCipherSuite directive specifies which ciphers are allowed in the negotiation with the client. While the SSLHonorCipherOrder causes the server's preferred ciphers to be used instead of the clients' specified preferences. The effective SSLCipherSuite (last one at server level and in each virtual host) is expanded with the local openssl ciphers -v; no resulting suite may be NULL/anonymous, EXPORT, RC4 or <= 56-bit, and SSLHonorCipherOrder must be On. Fails when no SSLCipherSuite is configured. Reads the main configuration (APACHE_CONF overrides; default /etc/apache2/apache2.conf, /etc/httpd/conf/httpd.conf or /usr/local/apache2/conf/httpd.conf) and every Include/IncludeOptional file. CIS marks this recommendation Manual; the automated check implements its audit procedure.
How it is checked
Audit method: Shell command
c=${APACHE_CONF:-}; if [ -z "$c" ]; then for f in /etc/apache2/apache2.conf /etc/httpd/conf/httpd.conf /usr/local/apache2/conf/httpd.conf /etc/apache2/httpd.conf; do [ -f "$f" ] && { c=$f; break; }; done; fi; [ -r "$c" ] || exit 1; R=$(awk 'tolower($1)=="serverroot"{v=$2; gsub(/"/,"",v); print v; exit}' "$c"); [ -n "$R" ] || R=$(dirname "$c"); shopt -s nocasematch; inc(){ local p g l; [ ${#FUNCNAME[@]} -lt 16 ] || return 0; p=$1; case $p in /*) ;; *) p=$R/$p;; esac; [ -d "$p" ] && p="$p/*"; for g in $p; do [ -f "$g" ] || continue; while IFS= read -r l || [ -n "$l" ]; do if [[ $l =~ ^[[:space:]]*include(optional)?[[:space:]]+\"?([^\"[:space:]]+) ]]; then inc "${BASH_REMATCH[2]}"; else printf '%s\n' "$l"; fi; done < "$g"; done; }; cfg=$(inc "$c" | sed -e 's/^[[:space:]]*//' -e '/^#/d' -e '/^$/d'); shopt -u nocasematch; eff(){ printf '%s\n' "$cfg" | awk -v k="$1" '{l=tolower($0)} l~/^<virtualhost/{vh=1; next} l~/^<\/virtualhost>/{if(v!="") print v; v=""; vh=0; next} tolower($1)==tolower(k){if(vh) v=$0; else g=$0} END{if(g!="") print g}'; }; s=$(eff SSLCipherSuite | awk 'tolower($1)=="sslciphersuite"{v=(NF>=3 && ($2=="SSL"||$2=="TLSv1.3"))?$3:$2; if(NF>=3 && $2=="TLSv1.3") next; gsub(/"/,"",v); print v}'); [ -n "$s" ] || { echo noncompliant; exit 0; }; command -v openssl >/dev/null || exit 1; bad=0; while IFS= read -r v; do o=$(openssl ciphers -v "$v" 2>/dev/null) || { bad=1; continue; }; printf '%s\n' "$o" | awk '$2!="TLSv1.3" && ($5~/None|RC4|\(40\)|\(56\)|DES\(56\)/ || $4~/None/ || $1~/EXP|NULL|ADH|AECDH/)' | grep -q . && bad=1; done <<< "$s"; eff SSLHonorCipherOrder | awk 'tolower($1)=="sslhonorcipherorder"{n++; if(tolower($2)!="on") b=1} END{exit !(n>0 && !b)}' || bad=1; [ "$bad" = 0 ] && echo compliant || echo noncompliant- Expected output
compliant
How it is fixed
Fix method: Guidance or infrastructure patch
SSLHonorCipherOrder On and SSLCipherSuite ALL:!EXP:!NULL:!LOW:!SSLv2:!RC4:!aNULL at server level and in every TLS virtual host. Then run apachectl configtest and reload Apache.
Properties
- Operating systems
- Any
- Tags
- apachetls
- Reference
- CIS Apache HTTP Server 2.4 Benchmark v2.4.0 - 7.5 Ensure Weak SSL/TLS Ciphers Are Disabled
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
tmaegis scan --target apache