twfiles - overview of files used by Tripwire and file backup process
The configuration file stores system-specific information, such as the location of Trip-
wire data files. The configuration settings are generated during the installation process,
but can be changed by the system administrator at any time. See the twconfig(4) man page
for a more complete discussion.
The policy file consists of a series of rules specifying the system objects that Tripwire
should monitor, and the data for each object that should be collected and stored in the
database file. Should unexpected changes occur, the policy file can describe the person
to be notified and the severity of the violation. See the policyguide.txt file in the
policy directory and the twpolicy(4) man page for a more complete discussion.
The database file serves as the baseline for integrity checking. After installation,
Tripwire creates the initial database file, a "snapshot" of the filesystem in a known
secure state. Later, when an integrity check is run, Tripwire compares each system object
described in the policy file against its corresponding entry in the database. A report is
created, and if an object has changed outside of constraints defined in the policy file, a
violation is reported. See the tripwire(8) and twprint(8) man pages for more information
on creating and maintaining database files.
Once the above three files have been created, Tripwire can run an integrity check and
search for any differences between the current system and the data stored in the "base-
line" Tripwire database. This information is archived into report files, a collection of
rule violations discovered during an integrity check. With the appropriate settings, a
report can also be emailed to one or more recipients. See the tripwire(8) and twprint(8)
man pages for information on creating and printing report files.
defaults: /etc/tripwire/site.key and /etc/tripwire/$(HOSTNAME)-local.key
It is critical that Tripwire files be protected from unauthorized access--an attacker who
is able to modify these files can subvert Tripwire operation. For this reason, all of the
above files are signed using public key cryptography to prevent unauthorized modification.
Two separate sets of keys protect critical Tripwire data files. One or both of these key
sets is necessary for performing almost every Tripwire task.
The site key is used to protect files that could be used across several systems. This
includes the policy and configuration files. The local key is used to protect files spe-
cific to the local machine, such as the Tripwire database. The local key may also be used
for signing integrity check reports. See the twadmin(8) man page for more information on
To prevent the accidental deletion of important data, Tripwire automatically creates
backup files whenever any Tripwire file is overwritten. The existing file will be renamed
with a .bak extension, and the new version of the file will take its place. Only one
backup copy for each filename can exist at any time. If a backup copy of a file already
exists, the older backup file will be deleted and replaced with the newer one.
File backup is an integral part of Tripwire, and cannot be removed or changed.
This man page describes Tripwire 2.3.1.
Permission is granted to make and distribute verbatim copies of this man page provided the
copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this man page under the
conditions for verbatim copying, provided that the entire resulting derived work is dis-
tributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this man page into another
language, under the above conditions for modified versions, except that this permission
notice may be stated in a translation approved by Tripwire, Inc.
Copyright 2000 Tripwire, Inc. Tripwire is a registered trademark of Tripwire, Inc. in the
United States and other countries. All rights reserved.
twintro(8), tripwire(8), twadmin(8), twprint(8), siggen(8), twconfig(4), twpolicy(4)
1 July 2000 TWFILES(5)