PHP开发中安全防范知识
PHP代码安全和XSS,SQL注入等对于各类网站的安全非常中用,尤其是UGC(User Generated Content)网站,论坛和电子商务网站,常常是XSS和SQL注入的重灾区。这里简单介绍一些基本编程要点, 相对系统安全来说,php安全防范更多要求编程人员对用户输入的各种参数能更细心.
php编译过程中的安全
建议安装Suhosin补丁,必装安全补丁
php.ini安全设置
register_global = off
magic_quotes_gpc = off
display_error = off
log_error = on
# allow_url_fopen = off
expose_php = off
open_basedir =
safe_mode = on
disable_function = exec,system,passthru,shell_exec,escapeshellarg,escapeshellcmd,proc_close,proc_open,dl,popen,show_source,get_cfg_var
safe_mode_include_dir =
DB SQL预处理
mysql_real_escape_string (很多PHPer仍在依靠addslashes防止SQL注入,但是这种方式对中文编码仍然是有问题的。addslashes的问题在于黑客可以用 0xbf27来代替单引号,GBK编码中0xbf27不是一个合法字符,因此addslashes只是将0xbf5c27,成为一个有效的多字节字符,其 中的0xbf5c仍会被看作是单引号,具体见这篇文章)。用mysql_real_escape_string函数也需要指定正确的字符集,否则依然可能 有问题。
prepare + execute(PDO)
ZendFramework可以用DB类的quote或者quoteInto, 这两个方法是根据各种数据库实施不用方法的,不会像mysql_real_escape_string只能用于mysql
用户输入的处理
无需保留HTML标签的可以用以下方法
strip_tags, 删除string中所有html标签
htmlspecialchars,只对””,”;”,”’”字符进行转义
htmlentities,对所有html进行转义
必须保留HTML标签情况下可以考虑以下工具:
HTML Purifier: HTML Purifier is a standards-compliant HTML filter library written in PHP.
PHP HTML Sanitizer: Remove unsafe tags and attributes from HTML code
htmLawed: PHP code to purify & filter HTML
上传文件
用is_uploaded_file和move_uploaded_file函数,使用HTTP_POST_FILES[]数组。并通过去掉上传目录的PHP解释功能来防止用户上传php脚本。
ZF框架下可以考虑使用File_upload模块
Session,Cookie和Form的安全处理
不要依赖Cookie进行核心验证,重要信息需要加密, Form Post之前对传输数据进行哈希, 例如你发出去的form元素如下:
POST回来之后对参数进行验证
$str = "";
foreach($_POST['H'] as $key=>$value) {
$str .= $key.$value;
}
if($_POST['hash'] != md5($str.$secret)) {
echo "Hidden form data modified"; exit;
}
PHP安全检测工具(XSS和SQL Insertion)
Wapiti - Web application security auditor(Wapiti - 小巧的站点漏洞检测工具) (SQL injection/XSS攻击检查工具)
安砚/使用方法:
apt-get install libtidy-0.99-0 python-ctypes python-utidylib
python wapiti.py http://Your Website URL/ -m GET_XSS
Pixy: XSS and SQLI Scanner for PHP( Pixy - PHP 源码缺陷分析工具)
安砚: apt-get install default-jdk

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