Chapter 10 Flashcards
hacker
in the linux world this refers to intelligent linux users… not necessarily malicious individuals
525
network server intermediaries
super server
super daemon
525
inetd
depreciated legacy super daemon.
525
inetd
Service Name
name of the service as listed in /etc/services file
526
inetd
Socket Type
tells the system what type of connection to expect like whether it is two way
526
inetd
Protocol
specifies which TCP/IP transport layer protocol will be used
526
inetd
Wait/No Wait
specifies whether the server connected to its client and freed the socket (nowait) or should process packets and then time out (wait)
526
inetd
User
username used to run the server. The root and nobody users were common choices
526
inetd
Parameters
Everything after the server name consisted of parameters that were passed to the server
526
xinetd
extended super daemon. It provides the functionality of inetd plus security options that are similar to those of TCP wrappers. controlled by the /etc/xinetd.d directory
528
fuser
determines the processes currently using network port
537
su
switch user
typed alone results in a prompt for root password. if the user types the password correctly
544
repudiation environment
a user can deny actions.
545
VNC
Virtual Network Computing
transfer’s data over the network unencrypted
555
who
shows you who is currently logged on to the system. It displays the username, their current terminal, and the time they logged into the system
547
who -a
adds far more information to the who command’s output
547
w command
shows who is logged into the system in addition to what they are doing and statistics about CPU usage
548
last command
current and historical data concerning users logging into and out of the system
not quite the last card I will write for Linux, but close
548
PAM
Pluggable Authentication Modules
called pam_limits. contains: domain type item value
551
/etc/security/limits.conf
domain type item value
domain field
describes the entity to which the limit applies. It can be a username; a group name, which takes the form @groupname, or an asterisk wildcard, which matches everybody
551
/etc/security/limits.conf
domain type item value
type field
specifies the limit as hard or soft. Hard limit is imposed by the system admin and cannot be exceeded under any circumstances
551
/etc/security/limits.conf
domain type item value
Limited Item
specifies what type of item is being limited. Examples include core (size of the core files), data (the size of a program’s data area), fsize (the size of files created by the user), nofile (the number of open data files), rss (the resident set size), stack (stack size), cpu (cpu time of a single process in minutes), nproc (the number of concurrent processes), maxlogins (the number of simultaneous logins), and priority (the process priority)
552
/etc/security/limits.conf
domain type item value
value field
specifies the value that’s to be applied to the limit
552
ulimit syntax
ulimit [options [limit]]
552
ulimit option
-c
core file limits the size of core dumps, which are files created for debugging purposes in certain types of program crashes
552
ulimit option
-f
limits the size of files that may be created by the shell
552
ulimit option
-n
limits the number of open file descriptors (not honored by most systems)
552
ulimit option
-u
limits the number of processes a user may run
552
ulimit option
-t
limits the total CPU time in seconds
552
ulimit option
-v
sets the total amount of virtual memory available to the shell
552
ulimit option
-s
sets the maximum stack size
552
ulimit option
-m
sets the maximum resident set size
552
ulimit option
-d
limits programs’ data set size
552
ulimit option
-l
sets the maximum size that may be locked into memory
552
ulimit option
-H
modifies only options to be hard
553
ulimit option
-S
modifies only options to be soft
553
ulimit option
-a
casues ulimit to report its current settings
553
growing the haystack password technique
adding a single letter repeatedly to increase security
543
GPG
Gnu Privacy Guard
not installed by default. open source reimplimentation of PGP
uses private and public key.
564
where does GPG keep it’s keys?
keyring
in the ~/.gnupg
564
pwconv
moves all password information from the /etc/passwd
541
pwck
ensures all of the files are in sync after conversion
541`