Friday, May 22, 2020

Learn A-Z Kali_Linux Commands For Beginerrs

Iemhacker-linux-command-for-beginner

All commands (A-Z) for Kali Linux here:
A
apropos Search Help manual pages (man -k)
apt-get Search for and install software packages (Debian/Ubuntu)
aptitude Search for and install software packages (Debian/Ubuntu)
aspell Spell Checker
awk Find and Replace text, database sort/validate/index
B
basename Strip directory and suffix from filenames
bash GNU Bourne-Again SHell
bc Arbitrary precision calculator language
bg Send to background
break Exit from a loop •
builtin Run a shell builtin
bzip2 Compress or decompress named file(s)
C
cal Display a calendar
case Conditionally perform a command
cat Concatenate and print (display) the content of files
cd Change Directory
cfdisk Partition table manipulator for Linux
chgrp Change group ownership
chmod Change access permissions
chown Change file owner and group
chroot Run a command with a different root directory
chkconfig System services (runlevel)
cksum Print CRC checksum and byte counts
clear Clear terminal screen
cmp Compare two files
comm Compare two sorted files line by line
command Run a command – ignoring shell functions •
continue Resume the next iteration of a loop •
cp Copy one or more files to another location
cron Daemon to execute scheduled commands
crontab Schedule a command to run at a later time
csplit Split a file into context-determined pieces
cut Divide a file into several parts
D
date Display or change the date & time
dc Desk Calculator
dd Convert and copy a file, write disk headers, boot records
ddrescue Data recovery tool
declare Declare variables and give them attributes •
df Display free disk space
diff Display the differences between two files
diff3 Show differences among three files
dig DNS lookup
dir Briefly list directory contents
dircolors Colour setup for `ls'
dirname Convert a full pathname to just a path
dirs Display list of remembered directories
dmesg Print kernel & driver messages
du Estimate file space usage
E
echo Display message on screen •
egrep Search file(s) for lines that match an extended expression
eject Eject removable media
enable Enable and disable builtin shell commands •
env Environment variables
ethtool Ethernet card settings
eval Evaluate several commands/arguments
exec Execute a command
exit Exit the shell
expect Automate arbitrary applications accessed over a terminal
expand Convert tabs to spaces
export Set an environment variable
expr Evaluate expressions
F
false Do nothing, unsuccessfully
fdformat Low-level format a floppy disk
fdisk Partition table manipulator for Linux
fg Send job to foreground
fgrep Search file(s) for lines that match a fixed string
file Determine file type
find Search for files that meet a desired criteria
fmt Reformat paragraph text
fold Wrap text to fit a specified width.
for Expand words, and execute commands
format Format disks or tapes
free Display memory usage
fsck File system consistency check and repair
ftp File Transfer Protocol
function Define Function Macros
fuser Identify/kill the process that is accessing a file
G
gawk Find and Replace text within file(s)
getopts Parse positional parameters
grep Search file(s) for lines that match a given pattern
groupadd Add a user security group
groupdel Delete a group
groupmod Modify a group
groups Print group names a user is in
gzip Compress or decompress named file(s)
H
hash Remember the full pathname of a name argument
head Output the first part of file(s)
help Display help for a built-in command •
history Command History
hostname Print or set system name
I
iconv Convert the character set of a file
id Print user and group id's
if Conditionally perform a command
ifconfig Configure a network interface
ifdown Stop a network interface
ifup Start a network interface up
import Capture an X server screen and save the image to file
install Copy files and set attributes
J
jobs List active jobs •
join Join lines on a common field
K
kill Stop a process from running
killall Kill processes by name
L
less Display output one screen at a time
let Perform arithmetic on shell variables •
ln Create a symbolic link to a file
local Create variables •
locate Find files
logname Print current login name
logout Exit a login shell •
look Display lines beginning with a given string
lpc Line printer control program
lpr Off line print
lprint Print a file
lprintd Abort a print job
lprintq List the print queue
lprm Remove jobs from the print queue
ls List information about file(s)
lsof List open files
M
make Recompile a group of programs
man Help manual
mkdir Create new folder(s)
mkfifo Make FIFOs (named pipes)
mkisofs Create an hybrid ISO9660/JOLIET/HFS filesystem
mknod Make block or character special files
more Display output one screen at a time
mount Mount a file system
mtools Manipulate MS-DOS files
mtr Network diagnostics (traceroute/ping)
mv Move or rename files or directories
mmv Mass Move and rename (files)
N
netstat Networking information
nice Set the priority of a command or job
nl Number lines and write files
nohup Run a command immune to hangups
notify-send Send desktop notifications
nslookup Query Internet name servers interactively
O
open Open a file in its default application
op Operator access
P
passwd Modify a user password
paste Merge lines of files
pathchk Check file name portability
ping Test a network connection
pkill Stop processes from running
popd Restore the previous value of the current directory
pr Prepare files for printing
printcap Printer capability database
printenv Print environment variables
printf Format and print data •
ps Process status
pushd Save and then change the current directory
pwd Print Working Directory
Q
quota Display disk usage and limits
quotacheck Scan a file system for disk usage
quotactl Set disk quotas
R
ram ram disk device
rcp Copy files between two machines
read Read a line from standard input •
readarray Read from stdin into an array variable •
readonly Mark variables/functions as readonly
reboot Reboot the system
rename Rename files
renice Alter priority of running processes
remsync Synchronize remote files via email
return Exit a shell function
rev Reverse lines of a file
rm Remove files
rmdir Remove folder(s)
rsync Remote file copy (Synchronize file trees)
S
screen Multiplex terminal, run remote shells via ssh
scp Secure copy (remote file copy)
sdiff Merge two files interactively
sed Stream Editor
select Accept keyboard input
seq Print numeric sequences
set Manipulate shell variables and functions
sftp Secure File Transfer Program
shift Shift positional parameters
shopt Shell Options
shutdown Shutdown or restart linux
sleep Delay for a specified time
slocate Find files
sort Sort text files
source Run commands from a file `.'
split Split a file into fixed-size pieces
ssh Secure Shell client (remote login program)
strace Trace system calls and signals
su Substitute user identity
sudo Execute a command as another user
sum Print a checksum for a file
suspend Suspend execution of this shell •
symlink Make a new name for a file
sync Synchronize data on disk with memory
T
tail Output the last part of file
tar Tape ARchiver
tee Redirect output to multiple files
test Evaluate a conditional expression
time Measure Program running time
times User and system times
touch Change file timestamps
top List processes running on the system
traceroute Trace Route to Host
trap Run a command when a signal is set(bourne)
tr Translate, squeeze, and/or delete characters
true Do nothing, successfully
tsort Topological sort
tty Print filename of terminal on stdin
type Describe a command •
U
ulimit Limit user resources •
umask Users file creation mask
umount Unmount a device
unalias Remove an alias •
uname Print system information
unexpand Convert spaces to tabs
uniq Uniquify files
units Convert units from one scale to another
unset Remove variable or function names
unshar Unpack shell archive scripts
until Execute commands (until error)
uptime Show uptime
useradd Create new user account
userdel Delete a user account
usermod Modify user account
users List users currently logged in
uuencode Encode a binary file
uudecode Decode a file created by uuencode
V
v Verbosely list directory contents (`ls -l -b')
vdir Verbosely list directory contents (`ls -l -b')
vi Text Editor
vmstat Report virtual memory statistics
W
wait Wait for a process to complete •
watch Execute/display a program periodically
wc Print byte, word, and line counts
whereis Search the user's $path, man pages and source files for a program
which Search the user's $path for a program file
while Execute commands
who Print all usernames currently logged in
whoami Print the current user id and name (`id -un')
wget Retrieve web pages or files via HTTP, HTTPS or FTP
write Send a message to another user
X
xargs Execute utility, passing constructed argument list(s)
xdg-open Open a file or URL in the user's preferred application.
yes Print a string until interrupted
. Run a command script in the current shell
!! Run the last command again
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ShodanEye: Collect Infomation About All Devices Connected To The Internet With Shodan


About ShodanEye
   This tool collects all information about all devices that are directly connected to the internet with the specified keywords that you enter. This way you get a complete overview.

   Here you can read the latest article about Shodan Eye: Shodan Eye Ethical Hacking Tool Release

   The types of devices that are indexed can vary enormously: from small desktops, refrigerators to nuclear power plants and everything in between. You can find everything using "your own" specified keywords. Examples can be found in a file that is attached:

   The information obtained with this tool can be applied in many areas, a small example:
  • Network security, keep an eye on all devices in your company or at home that are confronted with internet.
  • Vulnerabilities. And so much more.
   For additional data gathering, you can enter a Shodan API key when prompted. A Shodan API key can be found here

Shodan Eye Ethical Hacking Tool Release
   Before we start the year 2020, today there is a new big release ..! Please note, if you have already installed Shodan Eye on your computer, then it is worthwhile to read it carefully. Of course, even if you don't know this Shodan tool yet:
  • Shodan Eye goes from Python 2 to Python 3
  • Save the output of the Shodan Eye results
  • The entry of the Shodan password is no longer visible.

About Shodan Search Engine
   Shoan is a search engine that lets the user find specific types of computers (webcams, routers, servers, etc.) connected to the internet using a variety of filters. Some have also described it as a search engine of service banners, which are metadata that the server sends back to the client.

   What is the difference between Google or another search engine: The most fundamental difference is that Shodan Eye crawls on the internet, Google on the World Wide Web. However, the devices that support the World Wide Web are only a small part of what is actually connected to the Internet.

Before use this tool, you should note that:
  • This was written for educational purpose and pentest only.
  • The author will not be responsible for any damage ..!
  • The author of this tool is not responsible for any misuse of the information.
  • You will not misuse the information to gain unauthorized access.
  • This information shall only be used to expand knowledge and not for causing malicious or damaging attacks.
  • Performing any hacks without written permission is illegal..!

ShodanEye's screenshots:

ShodanEye Installation
   If you're using GNU/Linux, open your terminal and enter these commands:

   If you're a Windows user, follow these steps to install ShodanEye:
  • Download and run Python 3.7.x setup file from Python.org. On Install Python 3.7, enable Add Python 3.7 to PATH.
  • Download shodan-eye-master.zip file.>
  • Then unzip it.
  • Open CMD or PowerShell window at the Osueta folder you have just unzipped and enter these commands:
    pip install shodan
    python shodan-eye.py

Video Shodan Eye on YouTube:

Contact to the author:


Related word

Thursday, May 21, 2020

OSIF: An Open Source Facebook Information Gathering Tool


About OSIF
   OSIF is an accurate Facebook account information gathering tool, all sensitive information can be easily gathered even though the target converts all of its privacy to (only me), sensitive information about residence, date of birth, occupation, phone number and email address.

For your privacy and security, i don't suggest using your main account!

OSIF Installtion
   For Termux users, you must install python2 and git first:
pkg update upgrade
pkg install git python2


   And then, open your Terminal and enter these commands:   If you're Windows user, follow these steps:
  • Install Python 2.7.x from Python.org first. On Install Python 2.7.x Setup, choose Add python.exe to Path.
  • Download OSIF-master zip file.
  • Then unzip it.
  • Open CMD or PowerShell at the OSIF folder you have just unzipped and enter these commands:
    pip install -r requirements.txt
    python osif.py

Before you use OSIF, make sure that:
  • Turn off your VPN before using this tool.
  • Do not overuse this tool.
  • if you are confused how to use it, please type help to display the help menu or watch the video below.

How to use OSIF?


Related news


How To Spoof PDF Signatures

One year ago, we received a contract as a PDF file. It was digitally signed. We looked at the document - ignoring the "certificate is not trusted" warning shown by the viewer - and asked ourselfs:

"How do PDF signatures exactly work?"

We are quite familiar with the security of message formats like XML and JSON. But nobody had an idea, how PDFs really work. So we started our research journey.

Today, we are happy to announce our results. In this blog post, we give an overview how PDF signatures work and on top, we reveal three novel attack classes for spoofing a digitally signed PDF document. We present our evaluation of 22 different PDF viewers and show 21 of them to be vulnerable. We additionally evaluated 8 online validation services and found 6 to be vulnerable.

In cooperation with the BSI-CERT, we contacted all vendors, provided proof-of-concept exploits, and helped them to fix the issues and three generic CVEs for each attack class were issued: CVE-2018-16042CVE-2018-18688CVE-2018-18689.


Full results are available in the master thesis of Karsten Meyer zu Selhausen, in our security report, and on our website.

Digitally Signed PDFs? Who the Hell uses this?

Maybe you asked yourself, if signed PDFs are important and who uses them.
In fact, you may have already used them.
Have you ever opened an Invoice by companies such as Amazon, Sixt, or Decathlon?
These PDFs are digitally signed and protected against modifications.
In fact, PDF signatures are widely deployed in our world. In 2000, President Bill Clinton enacted a federal law facilitating the use of electronic and digital signatures in interstate and foreign commerce by ensuring the validity and legal effect of contracts. He approved the eSign Act by digitally signing it.
Since 2014, organizations delivering public digital services in an EU member state are required to support digitally signed documents, which are even admissible as evidence in legal proceedings.
In Austria, every governmental authority digitally signs any official document [§19]. In addition, any new law is legally valid after its announcement within a digitally signed PDF.
Several countries like Brazil, Canada, the Russian Federation, and Japan also use and accept digitally signed documents.
According to Adobe Sign, the company processed 8 billion electronic and digital signatures in the 2017 alone.

Crash Course: PDF and PDF Signatures

To understand how to spoof PDF Signatures, we unfortunately need to explain the basics first. So here is a breef overview.

PDF files are ASCII files. You can use a common text editor to open them and read the source code.

PDF header. The header is the first line within a PDF and defines the interpreter version to be used. The provided example uses version PDF 1.7. 
PDF body. The body defines the content of the PDF and contains text blocks, fonts, images, and metadata regarding the file itself. The main building blocks within the body are objects. Each object starts with an object number followed by a generation number. The generation number should be incremented if additional changes are made to the object.
In the given example, the Body contains four objects: Catalog, Pages, Page, and stream. The Catalog object is the root object of the PDF file. It defines the document structure and can additionally declare access permissions. The Catalog refers to a Pages object which defines the number of the pages and a reference to each Page object (e.g., text columns). The Page object contains information how to build a single page. In the given example, it only contains a single string object "Hello World!".
Xref table. The Xref table contains information about the position (byte offset) of all PDF objects within the file.
Trailer. After a PDF file is read into memory, it is processed from the end to the beginning. By this means, the Trailer is the first processed content of a PDF file. It contains references to the Catalog and the Xref table.

How do PDF Signatures work?

PDF Signatures rely on a feature of the PDF specification called incremental saving (also known as incremental update), allowing the modification of a PDF file without changing the previous content.
 
As you can see in the figure on the left side, the original document is the same document as the one described above. By signing the document, an incremental saving is applied and the following content is added: a new Catalog, a Signature object, a new Xref table referencing the new object(s), and a new Trailer. The new Catalog extends the old one by adding a reference to the Signature object. The Signature object (5 0 obj) contains information regarding the applied cryptographic algorithms for hashing and signing the document. It additionally includes a Contents parameter containing a hex-encoded PKCS7 blob, which holds the certificates as well as the signature value created with the private key corresponding to the public key stored in the certificate. The ByteRange parameter defines which bytes of the PDF file are used as the hash input for the signature calculation and defines 2 integer tuples: 
a, b : Beginning at byte offset a, the following b bytes are used as the first input for the hash calculation. Typically, a 0 is used to indicate that the beginning of the file is used while a b is the byte offset where the PKCS#7 blob begins.
c, d : Typically, byte offset c is the end of the PKCS#7 blob, while c d points to the last byte range of the PDF file and is used as the second input to the hash calculation.
    According to the specification, it is recommended to sign the whole file except for the PKCS#7 blob (located in the range between a b and c).

    Attacks

    During our research, we discovered three novel attack classes on PDF signatures:

    1. Universal Signature Forgery (USF)
    2. Incremental Saving Attack (ISA)
    3. Signature Wrapping Attack (SWA)

    In this blog post, we give an overview on the attacks without going into technical details. If you are more interested, just take a look at the sources we summarized for you here.

    Universal Signature Forgery (USF)

    The main idea of Universal Signature Forgery (USF) is to manipulate the meta information in the signature in such a way that the targeted viewer application opens the PDF file, finds the signature, but is unable to find all necessary data for its validation.

    Instead of treating the missing information as an error, it shows that the contained signature is valid. For example, the attacker can manipulate the Contents or ByteRange values within the Signature object. The manipulation of these entries is reasoned by the fact that we either remove the signature value or the information stating which content is signed.
    The attack seems trivial, but even very good implementations like Adobe Reader DC preventing all other attacks were susceptible against USF.

    Incremental Saving Attack (ISA)



    The Incremental Saving Attack (ISA) abuses a legitimate feature of the PDF specification, which allows to update a PDF file by appending the changes. The feature is used, for example, to store PDF annotations, or to add new pages while editing the file.

    The main idea of the ISA is to use the same technique for changing elements, such as texts, or whole pages included in the signed PDF file to what the attacker desires.
    In other words, an attacker can redefine the document's structure and content using the Body Updates part. The digital signature within the PDF file protects precisely the part of the file defined in the ByteRange. Since the incremental saving appends the Body Updates to the end of the file, it is not part of the defined ByteRange and thus not part of the signature's integrity protection. Summarized, the signature remains valid, while the Body Updates changed the displayed content.
    This is not forbidden by the PDF specification, but the signature validation should indicate that the document has been altered after signing.

    Signature Wrapping Attack (SWA)

    Independently of the PDFs, the main idea behind Signature Wrapping Attacks is to force the verification logic to process different data than the application logic.

    In PDF files, SWA targets the signature validation logic by relocating the originally signed content to a different position within the document and inserting new content at the allocated position. The starting point for the attack is the manipulation of the ByteRange value allowing to shift the signed content to different loctions within the file.

    On a very technical level, the attacker uses a validly signed document (shown on the left side) and proceeds as follows:


    • Step 1 (optional): The attacker deletes the padded zero Bytes within the Contents parameter to increase the available space for injecting manipulated objects.
    • Step 2: The attacker defines a new /ByteRange [a b c* d] by manipulating the c value, which now points to the second signed part placed on a different position within the document.
    • Step 3: The attacker creates a new Xref table pointing to the new objects. It is essential that the byte offset of the newly inserted Xref table has the same byte offset as the previous Xref table. The position is not changeable since it is refer- enced by the signed Trailer. For this purpose, the attacker can add a padding block (e.g., using whitespaces) before the new Xref table to fill the unused space.
    • Step 4: The attacker injects malicious objects which are not protected by the signature. There are different injection points for these objects. They can be placed before or after the malicious Xref table. If Step 1 is not executed, it is only possible to place them after the malicious Xref table.
    • Step 5 (optional): Some PDF viewers need a Trailer after the manipulated Xref table, otherwise they cannot open the PDF file or detect the manipulation and display a warning message. Copying the last Trailer is sufficient to bypass this limitation.
    • Step 6: The attacker moves the signed content defined by c and d at byte offset c*. Optionally, the moved content can be encapsulated within a stream object. Noteworthy is the fact that the manipulated PDF file does not end with %%EOF after the endstream. The reason why some validators throw a warning that the file was manipulated after signing is because of an %%EOF after the signed one. To bypass this requirement, the PDF file is not correctly closed. However, it will be still processed by any viewer.

    Evaluation

    In our evaluation, we searched for desktop applications validating digitally signed PDF files. We analyzed the security of their signature validation process against our 3 attack classes. The 22 applications fulfill these requirements. We evaluated the latest versions of the applications on all supported platforms (Windows, MacOS, and Linux).


    Authors of this Post

    Vladislav Mladenov
    Christian Mainka
    Karsten Meyer zu Selhausen
    Martin Grothe
    Jörg Schwenk

    Acknowledgements

    Many thanks to the CERT-Bund team for the great support during the responsible disclosure.
    We also want to acknowledge the teams which reacted to our report and fixed the vulnerable implementations.

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