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正在翻译：zky001 How to Configure Tripwire IDS on Debian
This article is about Tripwire installation and configuration on Debian OS. It is a host based Intrusion detection system (IDS) for Linux environment. Prime function of tripwire IDS is to detect and report any unauthorized change (files and directories ) on linux system. After tripwire installation, baseline database created first, tripwire monitors and detects changes such as new file addition/creation, file modification and user who changed it etc. If the changes are legitimate, you can accept the changes to update tripwire database.
Installation and Configuration
Tripwire installation on Debian VM is shown below.
# apt-get install tripwire
During installation, tripwire prompt for following configuration.
Site key Creation
Tripwire required a site passphrase to secure the tw.cfg tripwire configuration file and tw.pol tripwire policy file. Tripewire encrypte both files using given passphrase. Site passphrase is must even for a single instance tripwire.
Local Key passphrase
Local passphrase is needed for the protection of tripwire database and report files . Local key used by the tripwire to avoid unauthorized modification of tripwire baseline database.
Tripwire configuration path
Tripwire configuration saved in the /etc/tripwire/twcfg.txt file. It is used to generate encrypted configuration file tw.cfg.
Tripwire Policy path
Tripwire saves policies in /etc/tripwire/twpol.txt file . It is used for the generation of encrypted policy file tw.pol used by the tripwire.
Final installation of tripwire is shown in the following snapshot.
Tripwire Configuration file (twcfg.txt)
Tripwire configuration file (twcfg.txt) details is given below. Paths of encrypted policy file (tw.pol), site key (site.key) and local key (hostname-local.key) etc are given below.
ROOT =/usr/sbin
POLFILE =/etc/tripwire/tw.pol
DBFILE =/var/lib/tripwire/$(HOSTNAME).twd
REPORTFILE =/var/lib/tripwire/report/$(HOSTNAME)-$(DATE).twr
SITEKEYFILE =/etc/tripwire/site.key
LOCALKEYFILE =/etc/tripwire/$(HOSTNAME)-local.key
EDITOR =/usr/bin/editor
LATEPROMPTING =false
LOOSEDIRECTORYCHECKING =false
MAILNOVIOLATIONS =true
EMAILREPORTLEVEL =3
REPORTLEVEL =3
SYSLOGREPORTING =true
MAILMETHOD =SMTP
SMTPHOST =localhost
SMTPPORT =25
TEMPDIRECTORY =/tmp
Tripwire Policy Configuration
Configure tripwire configuration before generation of baseline database. It is necessary to disable few policies such as /dev , /proc ,/root/mail etc. Detailed policy file twpol.txt is given below.
@@section GLOBAL
TWBIN = /usr/sbin;
TWETC = /etc/tripwire;
TWVAR = /var/lib/tripwire;
#
# File System Definitions
#
@@section FS
#
# First, some variables to make configuration easier
#
SEC_CRIT = $(IgnoreNone)-SHa ; # Critical files that cannot change
SEC_BIN = $(ReadOnly) ; # Binaries that should not change
SEC_CONFIG = $(Dynamic) ; # Config files that are changed
# infrequently but accessed
# often
SEC_LOG = $(Growing) ; # Files that grow, but that
# should never change ownership
SEC_INVARIANT = +tpug ; # Directories that should never
# change permission or ownership
SIG_LOW = 33 ; # Non-critical files that are of
# minimal security impact
SIG_MED = 66 ; # Non-critical files that are of
# significant security impact
SIG_HI = 100 ; # Critical files that are
# significant points of
# vulnerability
#
# Tripwire Binaries
#
(
rulename = "Tripwire Binaries",
severity = $(SIG_HI)
)
{
$(TWBIN)/siggen -> $(SEC_BIN) ;
$(TWBIN)/tripwire -> $(SEC_BIN) ;
$(TWBIN)/twadmin -> $(SEC_BIN) ;
$(TWBIN)/twprint -> $(SEC_BIN) ;
}
{
/boot -> $(SEC_CRIT) ;
/lib/modules -> $(SEC_CRIT) ;
}
(
rulename = "Boot Scripts",
severity = $(SIG_HI)
)
{
/etc/init.d -> $(SEC_BIN) ;
#/etc/rc.boot -> $(SEC_BIN) ;
/etc/rcS.d -> $(SEC_BIN) ;
/etc/rc0.d -> $(SEC_BIN) ;
/etc/rc1.d -> $(SEC_BIN) ;
/etc/rc2.d -> $(SEC_BIN) ;
/etc/rc3.d -> $(SEC_BIN) ;
/etc/rc4.d -> $(SEC_BIN) ;
/etc/rc5.d -> $(SEC_BIN) ;
/etc/rc6.d -> $(SEC_BIN) ;
}
(
rulename = "Root file-system executables",
severity = $(SIG_HI)
)
{
/bin -> $(SEC_BIN) ;
/sbin -> $(SEC_BIN) ;
}
#
# Critical Libraries
#
(
rulename = "Root file-system libraries",
severity = $(SIG_HI)
)
{
/lib -> $(SEC_BIN) ;
}
#
# Login and Privilege Raising Programs
#
(
rulename = "Security Control",
severity = $(SIG_MED)
)
{
/etc/passwd -> $(SEC_CONFIG) ;
/etc/shadow -> $(SEC_CONFIG) ;
}
{
#/var/lock -> $(SEC_CONFIG) ;
#/var/run -> $(SEC_CONFIG) ; # daemon PIDs
/var/log -> $(SEC_CONFIG) ;
}
# These files change the behavior of the root account
(
rulename = "Root config files",
severity = 100
)
{
/root -> $(SEC_CRIT) ; # Catch all additions to /root
#/root/mail -> $(SEC_CONFIG) ;
#/root/Mail -> $(SEC_CONFIG) ;
/root/.xsession-errors -> $(SEC_CONFIG) ;
#/root/.xauth -> $(SEC_CONFIG) ;
#/root/.tcshrc -> $(SEC_CONFIG) ;
#/root/.sawfish -> $(SEC_CONFIG) ;
#/root/.pinerc -> $(SEC_CONFIG) ;
#/root/.mc -> $(SEC_CONFIG) ;
#/root/.gnome_private -> $(SEC_CONFIG) ;
#/root/.gnome-desktop -> $(SEC_CONFIG) ;
#/root/.gnome -> $(SEC_CONFIG) ;
#/root/.esd_auth -> $(SEC_CONFIG) ;
# /root/.elm -> $(SEC_CONFIG) ;
#/root/.cshrc -> $(SEC_CONFIG) ;
#/root/.bashrc -> $(SEC_CONFIG) ;
#/root/.bash_profile -> $(SEC_CONFIG) ;
# /root/.bash_logout -> $(SEC_CONFIG) ;
#/root/.bash_history -> $(SEC_CONFIG) ;
#/root/.amandahosts -> $(SEC_CONFIG) ;
#/root/.addressbook.lu -> $(SEC_CONFIG) ;
#/root/.addressbook -> $(SEC_CONFIG) ;
#/root/.Xresources -> $(SEC_CONFIG) ;
#/root/.Xauthority -> $(SEC_CONFIG) -i ; # Changes Inode number on login
/root/.ICEauthority -> $(SEC_CONFIG) ;
}
#
# Critical devices
#
(
rulename = "Devices & Kernel information",
severity = $(SIG_HI),
)
{
#/dev -> $(Device) ;
#/proc -> $(Device) ;
}
Tripwire Report
tripwire –check command checks the twpol.txt file and based on this file generates tripwire report which is shown below. If this is any error in the twpol.txt file, tripwire does not generate report.
Report in text form
root@VMdebian:/home/labadmin# tripwire --check
Parsing policy file: /etc/tripwire/tw.pol
*** Processing Unix File System ***
Performing integrity check...
Wrote report file: /var/lib/tripwire/report/VMdebian-20151024-122322.twr
Open Source Tripwire(R) 2.4.2.2 Integrity Check Report
Report generated by: root
Report created on: Sat Oct 24 12:23:22 2015
Database last updated on: Never
Report Summary:
=========================================================
Host name: VMdebian
Host IP address: 127.0.1.1
Host ID: None
Policy file used: /etc/tripwire/tw.pol
Configuration file used: /etc/tripwire/tw.cfg
Database file used: /var/lib/tripwire/VMdebian.twd
Command line used: tripwire --check
=========================================================
Rule Summary:
=========================================================
-------------------------------------------------------------------------------
Section: Unix File System
-------------------------------------------------------------------------------
Rule Name Severity Level Added Removed Modified
--------- -------------- ----- ------- --------
Other binaries 66 0 0 0
Tripwire Binaries 100 0 0 0
Other libraries 66 0 0 0
Root file-system executables 100 0 0 0
Tripwire Data Files 100 0 0 0
System boot changes 100 0 0 0
(/var/log)
Root file-system libraries 100 0 0 0
(/lib)
Critical system boot files 100 0 0 0
Other configuration files 66 0 0 0
(/etc)
Boot Scripts 100 0 0 0
Security Control 66 0 0 0
Root config files 100 0 0 0
Invariant Directories 66 0 0 0
Total objects scanned: 25943
Total violations found: 0
=========================Object Summary:================================
-------------------------------------------------------------------------------
# Section: Unix File System
-------------------------------------------------------------------------------
No violations.
===========================Error Report:=====================================
No Errors
-------------------------------------------------------------------------------
*** End of report ***
Open Source Tripwire 2.4 Portions copyright 2000 Tripwire, Inc. Tripwire is a registered
trademark of Tripwire, Inc. This software comes with ABSOLUTELY NO WARRANTY;
for details use --version. This is free software which may be redistributed
or modified only under certain conditions; see COPYING for details.
All rights reserved.
Integrity check complete.
Conclusion
In this article, we learned installation and basic configuration of open source IDS tool Tripwire. First it generates baseline database and detects any change (file/folder) by comparing it with already generated baseline. However, tripwire is not live monitoring IDS.
via: http://linoxide.com/security/configure-tripwire-ids-debian/