CVE-2018-18674 (PHP, published 2019-11-07T21:15Z)
Description: value: GNUBOARD5 5.3.1.9 has XSS that allows remote attackers to inject arbitrary web script or HTML via the "board tail contents" parameter, aka the adm/board_form_update.php bo_content_tail parameter.
Severity: MEDIUM (CVSS v3 base score: 6.1)
Weakness: CWE-79 \u2014 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Repository: https://github.com/gnuboard/gnuboard5
Files changed:
adm/board_form_update.php
adm/boardgroup_form.php
adm/config_form.php
adm/config_form_update.php
adm/menu_list.php
adm/menu_list_update.php
bbs/board_head.php
bbs/board_tail.php
bbs/password.php
Commit message: XSS 취약점 수정


Vulnerable code:
            <input type="text" name="gr_<?php echo $i ?>" value="<?php echo $gr['gr_'.$i] ?>" id="gr_<?php echo $i ?>" class="frm_input">
                <input type="text" name="cf_<?php echo $i ?>" value="<?php echo $config['cf_'.$i] ?>" id="cf_<?php echo $i ?>" class="frm_input" size="30">
    $me_link = $_POST['me_link'][$i];

    echo stripslashes($board['bo_mobile_content_head']);
    echo stripslashes($board['bo_content_head']);
    echo stripslashes($board['bo_mobile_content_tail']);
    echo stripslashes($board['bo_content_tail']);
//if ($board['bo_include_head']) { @include ($board['bo_include_head']); }
//if ($board['bo_content_head']) { echo stripslashes($board['bo_content_head']); }
//if ($board['bo_content_tail']) { echo stripslashes($board['bo_content_tail']); }
//if ($board['bo_include_tail']) { @include ($board['bo_include_tail']); }

Fixed code:
$_POST['bo_subject'] = strip_tags($_POST['bo_subject']);
$_POST['bo_mobile_subject'] = strip_tags($_POST['bo_mobile_subject']);

            <input type="text" name="gr_<?php echo $i ?>" value="<?php echo get_sanitize_input($gr['gr_'.$i]); ?>" id="gr_<?php echo $i ?>" class="frm_input">
                <input type="text" name="cf_<?php echo $i ?>" value="<?php echo get_sanitize_input($config['cf_'.$i]); ?>" id="cf_<?php echo $i ?>" class="frm_input" size="30">
$_POST['cf_title'] = strip_tags($_POST['cf_title']);


    var me_links = document.getElementsByName('me_link[]');
    var reg = /^javascript/; 

	for (i=0; i<me_links.length; i++){
        
	    if( reg.test(me_links[i].value) ){ 
        
            alert('링크에 자바스크립트문을 입력할수 없습니다.');
            me_links[i].focus();
            return false;
        }
    }

    $me_link = preg_match('/^javascript/', $_POST['me_link'][$i]) ? G5_URL : strip_tags($_POST['me_link'][$i]);
    
    echo html_purifier(stripslashes($board['bo_mobile_content_head']));
    echo html_purifier(stripslashes($board['bo_content_head']));
    echo html_purifier(stripslashes($board['bo_mobile_content_tail']));
    echo html_purifier(stripslashes($board['bo_content_tail']));
//if ($board['bo_include_head'] && is_include_path_check($board['bo_content_head'])) { @include ($board['bo_include_head']); }
//if ($board['bo_content_head']) { echo html_purifier(stripslashes($board['bo_content_head'])); }
//if ($board['bo_content_tail']) { echo html_purifier(stripslashes($board['bo_content_tail'])); }
//if ($board['bo_include_tail'] && is_include_path_check($board['bo_content_tail'])) { @include ($board['bo_include_tail']); }