Searching in the WordPress backend area in any of the Search Windows using a single quote code character/apostrophe will result in a 403 error.
Options:
1. Do not use the single quote code character/apostrophe when searching in the WordPress backend Dashboard/wp-admin area.
2. Whitelist/allow the single quote code character/apostrophe in search strings in the WordPress backend Dashboard/wp-admin area.
Copy this modified (single quote code character filters are removed) wp-admin .htaccess BPS Query String Exploits code below to this BPS wp-admin Custom Code text box:
# BEGIN BPSQSE-check BPS QUERY STRING EXPLOITS AND FILTERS
# WORDPRESS WILL BREAK IF ALL THE BPSQSE FILTERS ARE DELETED
RewriteCond %{HTTP_USER_AGENT} (%0A|%0D|%3C|%3E|%00) [NC,OR]
RewriteCond %{HTTP_USER_AGENT} (libwww-perl|wget|python|nikto|curl|scan|java|winhttp|HTTrack|clshttp|archiver|loader|email|harvest|extract|grab|miner) [NC,OR]
RewriteCond %{THE_REQUEST} \?\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} \/\*\ HTTP/ [NC,OR]
RewriteCond %{THE_REQUEST} etc/passwd [NC,OR]
RewriteCond %{THE_REQUEST} cgi-bin [NC,OR]
RewriteCond %{THE_REQUEST} (%0A|%0D) [NC,OR]
RewriteCond %{REQUEST_URI} owssvr\.dll [NC,OR]
RewriteCond %{HTTP_REFERER} (%0A|%0D|%3C|%3E|%00) [NC,OR]
RewriteCond %{HTTP_REFERER} \.opendirviewer\. [NC,OR]
RewriteCond %{HTTP_REFERER} users\.skynet\.be.* [NC,OR]
RewriteCond %{QUERY_STRING} [a-zA-Z0-9_]=http:// [NC,OR]
RewriteCond %{QUERY_STRING} [a-zA-Z0-9_]=(\.\.//?)+ [NC,OR]
RewriteCond %{QUERY_STRING} [a-zA-Z0-9_]=/([a-z0-9_.]//?)+ [NC,OR]
RewriteCond %{QUERY_STRING} \=PHP[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12} [NC,OR]
RewriteCond %{QUERY_STRING} (\.\./|%2e%2e%2f|%2e%2e/|\.\.%2f|%2e\.%2f|%2e\./|\.%2e%2f|\.%2e/) [NC,OR]
RewriteCond %{QUERY_STRING} ftp\: [NC,OR]
RewriteCond %{QUERY_STRING} http\: [NC,OR]
RewriteCond %{QUERY_STRING} https\: [NC,OR]
RewriteCond %{QUERY_STRING} \=\|w\| [NC,OR]
RewriteCond %{QUERY_STRING} ^(.*)/self/(.*)$ [NC,OR]
RewriteCond %{QUERY_STRING} ^(.*)cPath=http://(.*)$ [NC,OR]
RewriteCond %{QUERY_STRING} (\<|%3C).*script.*(\>|%3E) [NC,OR]
RewriteCond %{QUERY_STRING} (<|%3C)([^s]*s)+cript.*(>|%3E) [NC,OR]
RewriteCond %{QUERY_STRING} (\<|%3C).*iframe.*(\>|%3E) [NC,OR]
RewriteCond %{QUERY_STRING} (<|%3C)([^i]*i)+frame.*(>|%3E) [NC,OR]
RewriteCond %{QUERY_STRING} base64_encode.*\(.*\) [NC,OR]
RewriteCond %{QUERY_STRING} base64_(en|de)code[^(]*\([^)]*\) [NC,OR]
RewriteCond %{QUERY_STRING} GLOBALS(=|\[|\%[0-9A-Z]{0,2}) [OR]
RewriteCond %{QUERY_STRING} _REQUEST(=|\[|\%[0-9A-Z]{0,2}) [OR]
RewriteCond %{QUERY_STRING} ^.*(\(|\)|<|>).* [NC,OR]
RewriteCond %{QUERY_STRING} (NULL|OUTFILE|LOAD_FILE) [OR]
RewriteCond %{QUERY_STRING} (\.{1,}/)+(motd|etc|bin) [NC,OR]
RewriteCond %{QUERY_STRING} (localhost|loopback|127\.0\.0\.1) [NC,OR]
RewriteCond %{QUERY_STRING} (<|>|%0A|%0D|%3C|%3E|%00) [NC,OR]
RewriteCond %{QUERY_STRING} concat[^\(]*\( [NC,OR]
RewriteCond %{QUERY_STRING} union([^s]*s)+elect [NC,OR]
RewriteCond %{QUERY_STRING} union([^a]*a)+ll([^s]*s)+elect [NC,OR]
RewriteCond %{QUERY_STRING} (;|<|>|'|"|\)|%0A|%0D|%22|%27|%3C|%3E|%00).*(/\*|union|select|insert|drop|delete|update|cast|create|char|convert|alter|declare|order|script|set|md5|benchmark|encode) [NC,OR]
RewriteCond %{QUERY_STRING} (sp_executesql) [NC]
RewriteRule ^(.*)$ - [F,L]
# END BPSQSE-check BPS QUERY STRING EXPLOITS AND FILTERS
Click the Save wp-admin Custom Code button.
Go to the BPS Security Modes page and activate wp-admin BulletProof Mode.