Category: Hacking

Posted on by

Linux Privilege Escalation : Cron Jobs

Hello aspiring Ethical hackers. In this article you will learn how to exploit Cron jobs for Linux Privilege Escalation. If you are familiar with Windows Task Scheduler you will readily understand what cron is. Yes, it is used to schedule jobs or commands in Linux.
For example you have a Linux server and want to clean cache regularly once a day. You can do this manually everyday or schedule a job to do this daily without your intervention. Here’s where cron jobs assist you. You can assign a job in cron. Sometimes these jobs are assigned with root privileges and these can be exploited to gain root privileges. Let’s see it practically.

For this article, we have a target on which we already gained a shell. Then I ran the PE.sh privilege escalation script on the target to find ways to elevate privileges on the target.

As I scroll down the output of our PE.sh file, we can see our target has some cron jobs set.

linux privilege escalation with cron jobs

As you can see in the above images, we can set cron jobs monthly, daily or hourly. But our job here is to not schedule cron jobs. It is to exploit them. As we scroll down further, we can see the format of a cron job.

In the above image, you can see the exact format of a cron job. It is minutes first, hours, day of month, month and day of week. We can see a cron job named /opt/new_year.sh that is scheduled to run at the 00:00 time of first day of the first month of every year. That is the occasion of New Year.

But what does * * * * * mean? It means these cron jobs are scheduled to run every minute of every hour of every day of the week (i.e daily) , every month. That typically means these jobs run each and every minute. The important thing to notice here is that all these jobs are running as user “root”.

Let’s manipulate one the these scripts, let’s say /opt/my_script.sh. We have a SETUID bit set on “dash” shell, one of the shells installed on the target system.(We will see in a short while what SETUID is). This can be seen in the image below.

We are editing the my_script.sh file with a command “chmod u-s /bin/dash”. This will remove the SETUID bit. Wait for one minute and check the /bin/dash command.

The SETUID bit is removed. Not just that, we can add new users on the target system as shown below.

That’s how cron jobs can be exploited for linux privilege escalation.

Posted on by

Bypass Antivirus with AV | ATOR

Hello aspiring Ethical Hackers. In this article you will see how to bypass Antivirus with AV | ATOR. AV | Ator is a backdoor generator utility that uses cryptographic and injection techniques to bypass AV detection. The AV in AV | Ator stands for Anti Virus. Ator is character from the Italian Film Series “Ator” who is a swordsman, alchemist, scientist, magician, scholar and engineer with the ability to sometimes produce objects out of thin air.

ATOR takes C# shellcode as input, encrypts it with AES encryption and generates an executable file. ATOR uses various methods to bypass Anti Virus. Some of them are,

Portable executable injection : In portable executable injection, malicious code is written directly into a process (without a file on disk). Then, this code is executed by either invoking additional code or by creating a remote thread. The displacement of the injected code introduces the additional requirement for functionality to remap memory references.

Reflective DLL Injection : DLL injection is a technique used for running code within the address space of another process by forcing it to load a dynamic-link library. This will overcome the address relocation issue.

Thread Execution Hijacking : Thread execution hijacking is a process in which malicious code is injected into a thread of a process.

ATOR also has RTLO option that spoofs an executable file to look like having an “innocent” extension like ‘pdf’, ‘txt’ etc. E.g. the file “testcod.exe” will be interpreted as “tesexe.doc” and of course we can set a custom icon. ATOR can be run on both Windows and Linux. We need Mono to run ATOR on Linux.

Let’s see how to install ATOR in Kali Linux. Clone the ATOR repository from Github as shown below.

Then unzip the zip archive.

Then, Install Mono as shown below.

After moving into the extracted directory, there will be an AVIATOR executable. We just need to run it with Mono.

If you want to run ATOR in Windows, you can just download the compiled binaries from Github . When you run the executable, the ATOR GUI opens.

bypass antivirus with AV | ATOR

Let’s see all the options in detail.
1. It contains the encryption key that is used to encrypt the shellcode. Keep it default if you want.
2. It contains the IV used for AES encryption. Keep it default too.
3. Shellcode in C# format.
4. It will show the encrypted payload.
5. The location to which the generated executable is to be saved.
6. Various Injection techniques.
7. Set a Custom Icon to the executable.

Let’s create the shellcode using msfvenom.

Copy the shellcode generated above and paste it in the payload column. Click on “Encrypt” to see the encrypted payload in (4). Click on (7) to set a custom icon (we are using pdf icon). Select the path of the executable (5) and select the injection technique (6) and click on “Generate EXE” button. Here’s the payload.

Before executing it on the target, start a listener on the attacker machine.

As soon the payload is executed on the target, we will have a shell as shown below.

See how to bypass antivirus with

Posted on by

Cracking Wifi passwords automatically with Wifite

Hello aspiring ethical hackers. In this article, you will learn about a tool named Wifite. It is an automatic Wireless password cracking tool that tries almost all known methods of wireless cracking like Pixie-Dust attack, Brute-Force PIN attack, NULL PIN attack, WPA Handshake Capture + offline crack, The PMKID Hash Capture + offline crack and various WEP cracking attacks.
Wifite is installed by default on Kali Linux. Just like any wireless password cracking method, Wifite needs monitor mode to be enabled on the wireless interface as shown below. However, it automatically enables this monitor mode but if it fails to enable it, you can enable it manually as shown below.

Let’s see how Wifite works in cracking WEP, WPA and WPS enabled networks. Once everything is ready, open terminal and start Wifite using command as shown below.

wifite

It starts displaying all the wireless networks in your vicinity as shown below.

Let’s target the Access Point “Hack_Me_If_You_Can” which has WEP security enabled. Once you select the access point you want to target, hit CTRl + C and enter the number of that access point. In our case it is “1”.

As soon as you enter the number of that access point, Wifite tries out various attacks against the access point and grabs its password as shown below.

WEP is too easy. Let’s see how it fares in cracking WPA password. We start Wifite as shown above. Our target is once again “Hack_Me_If_You_Can”. However, as you can see it is secured with WPA now.

It starts attacking employing  various methods as shown below.

Now, let’s target a Access Point with WPS pin enabled.

As you can see, Wifite is successful in cracking WEP, WPA and WPS keys automatically without running any complex commands . Learn how to crack Wifi passwords with Besside-ng.

Posted on by — 1 Comment

Besside -ng : A tool to hack Wi – Fi automatically

Hello aspiring Ethical hackers. In this article, we will learn about a tool named Besside -ng, which can automatically crack WEP passwords and log WPA handshakes. This tool authored by Andrea Bittau is made in the line of another tool, Wesside-ng which only cracks WEP passwords automatically.

Before you run Besside-ng, monitor mode should be enabled on the wireless interface as shown below.

Once monitor mode is enabled on the wireless interface, we can run Besside-ng as shown below to automatically crack all the WEP passwords and log WPA handshakes.

If you want to crack the WEP password of a single Access Point, the command is as shown below

where “-c” is used to specify the channel the Wireless Access Point is running on and “-b” is the –bssid of the Wi -Fi access point.

how to use besside to crack wifi passwords

Besside-ng automatically starts creating traffic and cracking the WEP key as shown below.

As you can see in the above image, it cracked a 64bit ASCII WEP key in less than 1 minute. How about 64 bit hexadecimal WEP key that’s a bit complex.

This key was cracked in 63 seconds. How long it will take to crack the same key we cracked earlier with aircrack?

It took just 45 seconds to crack the password. This time, I generated a complex WEP key and tried again. The key was cracked in around 15 minutes as shown below.

Here’s the WEP key I set.

Just like cracking WEP, even Cracking WPA can be automated using tool besside-ng. To do this, we run besside-ng on the target wi-fi network.

Besside-ng automatically captures WPA handshake. Then all we have to do is run aircrack on the wpa.cap file.

The WPA key has been cracked successfully.

Posted on by

Beginners guide to PrintNightmare vulnerability

Hello, aspiring ethical hackers. In our previous blogpost, you learnt about EternalBlue vulnerability. In this article, you will learn about another critical vulnerability called PrintNightmare vulnerability.

What is PrintNightmare vulnerability?

PrintNightmare is a vulnerability that affects the Microsoft’s Windows operating systems. This vulnerability is present in the print spooler service of Microsoft Windows. The printer spooler service is used for printing services and is turned on by default. The versions of Windows vulnerable to PrintNightmare include Windows 7 to Windows 10 and windows Server 2008 to the latest version of Windows Servers.

Proof of Concept (PoC)

The PrintNightmare vulnerability has two variants : one allows unauthorized remote code execution (CVE-2021-34527) and the other allows unauthorized privilege escalation (CVE-2021-1675). In this article, readers will see a proof of concept for exploiting the privilege escalation vulnerability. For this, we will use Windows 10 version 1809 as target system. The PowerShell Script we used in this demo can be downloaded from GitHub.

In this scenario, let’s imagine I already have access to the target machine as a user with low privileges. The first thing we have to do is to confirm if the printer spooler service is running on the target system or not. This can be done using PowerShell command given below.

"Get-Service -Name "spooler""

The print spooler service is running on the target system. As you can see in the images below, I am running as a user with very limited privileges.

Next, I download the PowerShell script and import it using command shown below.

Import-Module .\<script Name>

Once the module is successfully imported, I execute the script with command to create a new user as shown below. 

"Invoke-Nightmare -NewUser "<username to create>" -NewPassword  <password for that new user> DriverName "PrintMe""


This command will create a new user on the target system with administrator privileges.

How to exploit printnightmare

In the image above, you can see that a new user named “hacker” has been created. Now, let’s check the privileges of this user.

As you can see, the new user we created belongs to the local administrators group. You can login as that user.

The PoC is successful.