You can use it like this for filtering
<?php
$badSearchInput = 'Domain\username';
$escapedSearchInput = ldap_escape($badSearchInput, null, LDAP_ESCAPE_FILTER);
?>
(PHP 5 >= 5.6.0, PHP 7)
ldap_escape — Escape a string for use in an LDAP filter or DN
$value
[, string $ignore
[, int $flags
]] )
Escapes value for use in the context implied by
flags.
valueThe value to escape.
ignoreCharacters to ignore when escaping.
flags
The context the escaped string will be used in:
LDAP_ESCAPE_FILTER for filters to be used with
ldap_search(), or
LDAP_ESCAPE_DN for DNs.
Returns the escaped string.
You can use it like this for filtering
<?php
$badSearchInput = 'Domain\username';
$escapedSearchInput = ldap_escape($badSearchInput, null, LDAP_ESCAPE_FILTER);
?>