st_snapshot1

Overview

st_snapshot calculates checksums and stats ownership and permissions of critical system files.

This script is typically run in either root-mode or public-mode. Running this script in root-mode requires root priviliges. One is adviced to set up a dedicated user account for running this script in public mode.

In root-mode, the files snapshot_root.list and snapshot_root.homelist are typically passed as arguments. These pattern files are read by the script and contain names of files and directories; listing a directory in such a pattern file is equivalent to listing all files which live in the directorytree with this directory as root.

snapshot_root.list could e.g. read

 # snapshot_root.list - files and directories we wanna get
 # monitored: we wanna get a note once these files, or any file
 # under these directories, gets created, gets rm-ed, gets
 # permissions or contents changed.  these notices will not
 # include the possibly secret contents of these files
 #
 # this file gets read by st_systraq
 /etc/group
 /etc/gshadow
 /etc/hosts.allow
 /etc/hosts.deny
 /etc/hosts.equiv
 /etc/lilo.conf
 /etc/passwd
 /etc/postfix/server.pem
 /etc/shadow
 /etc/skel
 /etc/ssh

Equivalent files snapshot_pub.list and snapshot_pub.homelist should be on the system. These files should contain all worldreadable to be monitored files. This allows for running this script as root only in those cases where it's needed: when reading files, readable for root only.

The homelist files contain files and directories which should get monitored for every homedirectory on the system. snapshot_pub.homelist could e.g. contain:

 .profile
 .cshrc
 .tcshrc
 .login
 .logout
 .bash_profile
 .bashrc
 .exrc
 .nexrc

As a special case, when the environment variable ST_OPHOMES is set to a non-empty string (typically when running in public mode), we stat the permissions on all homedirectories themselves.

The produced snapshot is printed to stdout. The output when running in public mode could look like:

 # ownership and permissions of homedirs
 drwxr-xr-x root root /bin
 drwxr-xr-x root root /dev
 drwxr-sr-x root staff /home
 drwxr-sr-x joostvb joostvb /home/joostvb
 drwxr-xr-x root root /usr/sbin
 drwxr-xr-x root root /var
 # sha256sum of critical pub files
 4d3cd13d6dbc10e2e3ccb9477cbc9eb9b76302454c276d5771ae0b10a5fbb4d2  /home/joostvb/.ssh/id_rsa.pub
 eb8d83e0246f761a21bdfb13a03fac634ed7c3b7dde4c2efddd7b2838d32596f  /var/qmail/alias/.bashrc
 4e371f9a11f5a2464d3d5c952e58e24f73b377d33767ed93b2082fcb59a647fe  /etc/zlogin
 # ownership and permissions of critical pub files
 -rw-rw-r-- joostvb joostvb /home/joostvb/.ssh/id_rsa.pub
 -rw-r--r-- joostvb joostvb /home/joostvb/.ssh/authorized_keys

Environment

ST_OPHOMES - non-empty in case permissions on all homedirectories should be printed

ST_SUM - command for calculating file checksums. E.g. sha256sum, sha512sum, sha384sum, sha224sum or sha1sum.