[Xymon] Xymon 4.3.25 - Important Security Update

[J.C. Cleaver]

Hello all,


Xymon 4.3.25 has been released and is now available for download at
https://sourceforge.net/projects/xymon/


Version 4.3.25 includes fixes for several security issues in the server
component of the Xymon monitoring system, which are further detailed
below. In addition, there are several other feature additions, and several
bug fixes and reliability improvements.

Full release notes and a Changelog are available at
https://sourceforge.net/projects/xymon/files/Xymon/4.3.25/

These issues affect all versions of Xymon 4.3.x prior to 4.3.25, as well
as the obsolete 4.1.x and 4.2.x versions. All Xymon users are strongly
encouraged to upgrade their server component.


We would like to greatly thank Markus Krell for his responsible reporting
of these issues and for his assistance in testing their resolution.


And as always, thank you to everyone who has contributed code or submitted
feature suggestions or bug reports to the Xymon project.


Regards,

Japheth "J.C." Cleaver
Xymon 4.x Maintainer



* CVE-2016-2054: Buffer overflow in xymond handling of "config" command:
The xymond daemon performs an unchecked copying of a user-supplied
filename to a fixed-size buffer when handling a "config" command. This
may be used to trigger a buffer overflow in xymond, possibly resulting
in remote code execution and/or denial of service of the Xymon
monitoring system. This code will run with the privileges of the xymon
userid.

This bug may be triggered by anyone with network access to the xymond
service on port 1984, unless access has been restricted with the
"--status-senders" option (a non-default configuration).

This bug has been patched in Xymon 4.3.25.


* CVE-2016-2055: Access to possibly confidential files in the Xymon
configuration directory:
The xymond daemon will allow anyone with network access to the xymond
network port (1984)  to download configuration files in the Xymon "etc"
directory. In a default installation, the Apache htaccess file
"xymonpasswd" controlling access to the administrator webpages is
installed in this directory and is therefore available for download. The
passwords in the file are hashed, but may then be brute-forced off-line.

This bug may be triggered by anyone with network access to the xymond
service on port 1984, unless access has been restricted with the
"--status-senders" option (a non-default configuration).

Administrators of existing installations should ensure that the
xymonpasswd file is not readable by the userid running the xymond
daemon. Permissions should be: Owner=webserver UID, group=webserver GID,
mode rw-rw--- (600). This will be the default configuration starting
with Xymon 4.3.25. In addition, the "config" command will only allow
access to regular files. By default, only files ending in ".cfg" may be
directly retrieved, although this can be overridden by the administrator,
and config files may include other files and directories using existing
directives.

Alternatively, the file may be moved to a location outside the Xymon
configuration directory. The Xymon cgioptions.cfg file must then be
edited so CGI_USERADM_OPTS and CGI_CHPASSWD_OPTS include
"--passwdfile=FILENAME".


* CVE-2016-2056: Shell command injection in the "useradm" and "chpasswd"
web applications:
The useradm and chpasswd web applications may be used to administer
passwords for user authentication in Xymon, acting as a web frontend to
the Apache "htpasswd" application. The htpasswd command is invoked via a
shell command, and it is therefore possible to inject arbitrary commands
and have them executed with the privileges of the webserver (CGI) user.

This bug can only be triggered by web users with access to the Xymon
webpages, who are already authenticated as Xymon users. However, when
combined with CVE-2016-xxxx which allows for off-line cracking of
password hashes, this bug may be exploitable by others.

This bug has been patched in Xymon 4.3.25.


* CVE-2016-2057: Incorrect permissions on IPC queues used by the xymond
daemon can bypass IP access filtering:
An IPC message queue used by the xymon daemon is created with
world-write permissions, allowing a local user on the Xymon master
server to inject all types of messages into Xymon, bypassing any
IP-based access controls.

Exploitation of this bug requires local access to the Xymon master server.

This bug has been patched in Xymon 4.3.25.


* CVE-2016-2058: Javascript injection in "detailed status webpage" of
monitoring items:
A status-message sent from a Xymon client may contain any data,
including HTML, which will be included on the "detailed status" page
available via the Xymon status webinterface. A malicious user may send a
status message containing custom Javascript code, which will then be
rendered in the browser of the user viewing the status page.

Exploitation of this bug requires that you can control the contents of a
status message sent to Xymon, which is possible if you control one of
the servers monitored by Xymon, or the Xymon master server. Also, the
bug requires a user to actually view the "detailed status" webpage.

This bug has been patched in Xymon 4.3.25 by including a
"Content-Security-Policy" HTTP header in the response sent to the
browser. This means that older browsers may still be vulnerable to this
issue.


* CVE-2016-2058: XSS vulnerability via malformed acknowledgment messages:
(Note that this uses the same CVE id as the Javascript injection issue)
The message sent by a user to indicate acknowledgment of an alert is not
HTML-escaped before being displayed on the status webpage, which may be
used to trigger a cross-site scripting vulnerability.

Exploitation of this bug requires that the attacker is able to
acknowledge an alert status. This requires user-authenticated access to
the Xymon webpages, or that the user receives a message (usually via
e-mail) containing the authentication token for the acknowledgment.

This bug has been patched in Xymon 4.3.25.