The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
None
C
There is no impact on the confidentiality of the system; the attacker does not gain the ability to read any data.
Integrity
None
I
There is no impact on the integrity of the system; the attacker does not gain the ability to modify any files or information on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Horde 3.1.6 arbitrary file inclusion vulnerability, proof of concept & patch.
A severe security vulnerability affects any unix distribution running version 3.1.6 of the Horde webmail client included in most popular webhosting control panels. All previous versions are also affected and it is believed although not yet proven that Horde Groupware is also vulnerable.
Details are as follows:
David Collins and Patrick Pelanne along with the rest of the HostGator.com LLC support team discovered that Horde was not properly sanitizing POST variables for several options including it's themes. By maliciously modifying POST data sent to the client the attacker can modify the location of the theme variable and Horde will subsequently insert this information into it's database. By modifying this POST variable one can allow for directory traversal and file inclusion which can lead to full root privilege escalation.
Proof of concept:
Data injected through malicious tampering of POST data:
mysql> select * from horde_prefs where pref_uid='bbarker (at) hostgator (dot) com [email concealed]' and pref_name='theme';
+-------------------------+------------+-----------+--------------------
------------------------------------------------------------------------
--------------------------------+
| pref_uid | pref_scope | pref_name | pref_value |
+-------------------------+------------+-----------+--------------------
------------------------------------------------------------------------
--------------------------------+
| bbarker (at) hostgator (dot) com [email concealed] | horde | theme | ../../../../../../../../../../../../../../../../../../tmp/.horde/imp/att
achments/bbarker (at) hostgator (dot) com [email concealed]/1204804402/t.txt |
Shown above, the malicious POST variable was inserted into the database and now points to the malicious code denoted by t.txt
A truncated strace shows the access and execution of the malicious code when the user enters the Horde webmail client:
31852 lstat64("/usr", {st_dev=makedev(3, 3), st_ino=2, st_mode=S_IFDIR|0755, st_nlink=18, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=16, st_size=4096, s$
31852 lstat64("/usr/local", {st_dev=makedev(3, 3), st_ino=608001, st_mode=S_IFDIR|0755, st_nlink=26, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=16, st_s$
31852 lstat64("/usr/local/cpanel", {st_dev=makedev(3, 3), st_ino=18539, st_mode=S_IFDIR|0711, st_nlink=37, st_uid=0, st_gid=10, st_blksize=4096, st_blocks=8$
31852 lstat64("/usr/local/cpanel/base", {st_dev=makedev(3, 3), st_ino=85078, st_mode=S_IFDIR|0755, st_nlink=21, st_uid=0, st_gid=0, st_blksize=4096, st_bloc$
31852 lstat64("/usr/local/cpanel/base/horde", {st_dev=makedev(3, 3), st_ino=85388, st_mode=S_IFDIR|0755, st_nlink=21, st_uid=32002, st_gid=32004, st_blksize$
31852 lstat64("/usr/local/cpanel/base/horde/config", {st_dev=makedev(3, 3), st_ino=115868, st_mode=S_IFDIR|0755, st_nlink=2, st_uid=32002, st_gid=32004, st_$
31852 lstat64("/usr/local/cpanel/base/horde/themes", {st_dev=makedev(3, 3), st_ino=86796, st_mode=S_IFDIR|0755, st_nlink=28, st_uid=32002, st_gid=32004, st_$
31852 lstat64("/tmp", {st_dev=makedev(7, 1), st_ino=2, st_mode=S_IFDIR|S_ISVTX|0777, st_nlink=9, st_uid=0, st_gid=0, st_blksize=4096, st_blocks=64, st_size=$
31852 lstat64("/tmp/.horde", {st_dev=makedev(7, 1), st_ino=38609, st_mode=S_IFDIR|0700, st_nlink=3, st_uid=32002, st_gid=32004, st_blksize=4096, st_blocks=2$
31852 lstat64("/tmp/.horde/imp", {st_dev=makedev(7, 1), st_ino=38610, st_mode=S_IFDIR|0700, st_nlink=3, st_uid=32002, st_gid=32004, st_blksize=4096, st_bloc$
31852 lstat64("/tmp/.horde/imp/attachments", {st_dev=makedev(7, 1), st_ino=38611, st_mode=S_IFDIR|0700, st_nlink=3, st_uid=32002, st_gid=32004, st_blksize=4$
31852 lstat64("/tmp/.horde/imp/attachments/patrick (at) hostgator (dot) com [email concealed]", {st_dev=makedev(7, 1), st_ino=38612, st_mode=S_IFDIR|0700, st_nlink=3, st_uid=32002, st$
31852 lstat64("/tmp/.horde/imp/attachments/patrick (at) hostgator (dot) com [email concealed]/1204804402", {st_dev=makedev(7, 1), st_ino=38613, st_mode=S_IFDIR|0700, st_nlink=2, st_ui$
31852 lstat64("/tmp/.horde/imp/attachments/patrick (at) hostgator (dot) com [email concealed]/1204804402/t.
txt", {st_dev=makedev(7, 1), st_ino=38614, st_mode=S_IFREG|0600, st_nlink=1,$
31852 open("/tmp/.horde/imp/attachments/patrick (at) hostgator (dot) com [email concealed]/1204804402/t.txt
", O_RDONLY) = 4
We have also included a patch below for this vulnerability tested on Horde v2.105.4.8 2006/07/29 16:49:19
--- horde/lib/Horde/Prefs.php 2008-03-06 21:14:38.000000000 -0600
+++ horde/lib/Horde/Prefs.patched 2008-03-06 20:10:56.000000000 -0600
@@ -325,12 +325,23 @@
}
return (isset($this->_prefs[$pref]['v'])) ?
- ($convert ?
+ $this->_fixhole($pref,$convert ?
$this->convertFromDriver($this->_prefs[$pref]['v'], $charset) :
$this->_prefs[$pref]['v']) :
null;
}
+function _fixhole($pref,$value) {
+ $sanitize = '/^[a-z0-9._-]+$/i';
+ if (preg_match($sanitize, $value) && $pref == 'theme') {
+ return $value;
+ } elseif ($pref == 'theme') {
+ return "mozilla";
+ } else {
+ return $value;
+ }
+}
+
function __get($name)
{
return $this->getValue($name);
-- Begin Signature --
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