Fix stored XSS in HTML report via unescaped Location: header (#3090)

pr_url() and pr_boldurl() interpolated their argument directly into
<a href="$1">$1</a> without HTML escaping. The most notable caller
passes the raw HTTP Location: header from the scanned server, so a
malicious HTTPS target could inject arbitrary HTML/JS into an
operator's --htmlfile report. Route both the href attribute and the
link text through the existing html_reserved() escaper, matching the
pattern already used by every other pr_* HTML-output function.

CHANGELOG.md

@@ -13,6 +13,7 @@
 * Enable IPv6 automagically, i.e. if target via IPv6 is reachable just (also) scan it
 * Detect and show DNS HTTPS RR (RFC 9460)
 * Provide an FAQ
+* Security fix: HTML-escape URLs in the HTML report to prevent stored XSS from a server-controlled `Location:` header (#3090)
 
 ### Features implemented / improvements in 3.2
 

CREDITS.md

@@ -71,6 +71,9 @@ Full contribution, see git log.
 * Christian Dresen
    - Dockerfile
 
+* Eric Gu
+  - HTML report XSS fix (escape server-controlled URLs, #3090)
+
 * enxio
    - support for TN3270/telnet STARTTLS
 

testssl.sh

@@ -760,8 +760,8 @@ tmln_fixme() { tmln_warning "Fixme: $1"; }
 pr_fixme()   { pr_warning "Fixme: $1"; }
 prln_fixme() { prln_warning "Fixme: $1"; }
 
-pr_url()     { tm_out "$1"; html_out "<a href=\"$1\" style=\"color:black;text-decoration:none;\">$1</a>"; }
-pr_boldurl() { tm_bold "$1"; html_out "<a href=\"$1\" style=\"font-weight:bold;color:black;text-decoration:none;\">$1</a>"; }
+pr_url()     { tm_out "$1"; html_out "<a href=\"$(html_reserved "$1")\" style=\"color:black;text-decoration:none;\">$(html_reserved "$1")</a>"; }
+pr_boldurl() { tm_bold "$1"; html_out "<a href=\"$(html_reserved "$1")\" style=\"font-weight:bold;color:black;text-decoration:none;\">$(html_reserved "$1")</a>"; }
 
 ### color switcher (see e.g. https://linuxtidbits.wordpress.com/2008/08/11/output-color-on-bash-scripts/
 ###                          https://www.tldp.org/HOWTO/Bash-Prompt-HOWTO/x405.html