1AUDISP-PRELUDE:(8) System Administration Utilities AUDISP-PRELUDE:(8)
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6 audisp-prelude - plugin for IDMEF alerts
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9 audisp-prelude [ --test ]
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12 audisp-prelude is a plugin for the audit event dispatcher daemon, aud‐
13 ispd, that uses libprelude to send IDMEF alerts for possible Intrusion
14 Detection events. This plugin requires connecting to a prelude-manager
15 to record the events it sends. This plugin will analyze audit events in
16 realtime and send detected events to the prelude-manager for correla‐
17 tion, recording, and display.
18 Events that are currently supported are: Logins, Forbidden Login Loca‐
20 tion, Max Concurrent Sessions, Max Login Failures, Forbidden Login
21 Time, SE Linux AVCs, SE Linux Enforcement Changes, Abnormal Program
22 Termination, Promiscuous Socket Changes, and watched account logins.
23
26 --test Take input from stdin and write prelude events to stdout but
27 does not send them to the prelude-manager. This can be used for
28 debugging or testing the system with suspicious log files when
29 you do not want it to alert or react.
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33 This sensor has to be registered with the prelude-manager before it
34 will work properly. If the prelude-manager is on the same host as the
35 sensor, you will need to open two windows to register. If not, you will
36 have to adjust this example to fit your environment.
37 In one window, type:
39 prelude-admin register auditd "idmef:w" localhost --uid 0 --gid 0
41 In another, type:
43 prelude-admin registration-server prelude-manager
45 Follow the on-screen instructions to complete the registration.
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50 If you are aggregating multiple machines, you should enable node infor‐
51 mation in the audit event stream. You can do this in one of two places.
52 If you want computer node names written to disk as well as sent in the
53 realtime event stream, edit the name_format option in
54 /etc/audit/auditd.conf. If you only want the node names in the realtime
55 event stream, then edit the name_format option in /etc/audisp/aud‐
56 ispd.conf. Do not enable both as it will put 2 node fields in the event
57 stream.
58 At this point, if you want have audit: forbidden login location, max
60 concurrent sessions, max login failures, and forbidden login time anom‐
61 alies being reported, you have to setup pam modules correctly. The pam
62 modules are respectively: pam_access, pam_limits, pam_tally2, and
63 pam_time. Please see the respective pam module man pages for any
64 instructions.
65 For performance reasons, some audit events will not produce syscall
67 records which contain additional information about events unless there
68 is at least one audit rule loaded. If you do not have any additional
69 audit rules, edit /etc/audit/audit.rules and add something simple that
70 won't impact performace like this: -w /etc/shadow -p wa. This rule will
71 watch the shadow file for writes or changes to its attributes. The
72 additional audit information provided by having at least one rule will
73 allow the plugin to give a more complete view of the alert it is send‐
74 ing.
75 If you are wanting to get alerts on watched syscalls, watched files,
77 watched execution, or something becoming executable, you need to add
78 some keys to your audit rules. For example, if you have the following
79 audit watch in /etc/audit/audit.rules:
80 -w /etc/shadow -p wa
82 and you want idmef alerts on this, you need to add -k ids-file-med or
84 something appropriate to signal to the plugin that this message is for
85 it. The format of the key has a fixed format of keywords separated by a
86 dash. It follows the form of ids-type-severity. The type can be either
87 sys, file, exec, or mkexe depending on whether you want the event to be
88 considered a watched_syscall, watched_file, watched_exec, or
89 watched_mk_exe respectively. The severity can be either info, low, med,
90 or hi depending on how urgent you would like it to be.
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94 To alert on any use of the personality syscall: -a exit,always -S per‐
95 sonality -k ids-sys-med
96 To alert on a user failing to access the shadow file: -a always,exit -F
98 path=/etc/shadow -F perms=wa -F success=0 -k ids-file-med
99 To alert on the execution of a program: -w /bin/ping -p x -k ids-exe-
101 info
102 To alert on users making exe's in their home dir (takes 2 rules): -a
104 exit,always -S fchmodat -F dir=/home -F a2&0111 -F filetype=file -k
105 ids-mkexe-hi -a exit,always -S fchmod,chmod -F dir=/home -F a1&0111 -F
106 filetype=file -k ids-mkexe-hi
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110 /etc/audisp/plugins.d/au-prelude.conf, /etc/audit/auditd.conf,
111 /etc/audisp/audispd.conf, /etc/audisp/audisp-prelude.conf
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114 audispd(8), prelude-manager(1), auditd.conf(8), audispd.conf(8), aud‐
115 isp-prelude.conf(5).
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118 Steve Grubb
119Red Hat Dec 2008 AUDISP-PRELUDE:(8)