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Evil Twin Attack

Hello aspiring ethical hackers. In this article, you will learn about Evil Twin Attack. Till now in our blog, readers have learnt about various wireless hacking tutorials like cracking WEP, cracking WPA/WPA2 and cracking WPS. Almost all of these hacking methods involved brute forcing or password cracking. What if there was another easier way to hack wireless networks without the need of brute forcing.

Well, Evil Twin Attack is one such attack. An evil twin attack is a wireless attack in which a fake Wi-Fi access point is set up with the same SSID as that of the original one. This fake access point appears to be legitimate but is actually set up to eavesdrop on wireless communications of the original one. The evil twin is the wireless LAN equivalent of the phishing scam.

Since it has the same name, it’s called twin and as it is malicious it can be termed Evil Twin. The aim of this attack is to confuse users trying to connect to the target Wi-Fi network and make them connect to the Evil Twin instead and thus capture sensitive data. Let’ s see it practically. There are many tools that can be used for this attack but let’s use a tool called Wifiphisher because it’s the simplest one. Our Attacker system is Kali Linux. Wifiphisher can be installed on Kali Linux as shown below.

Once installation is finished, Wifiphisher can be started using command.

sudo wifiphisher

Then the tool will prompt you to select the Wi-Fi Access Point of which you want to create an Evil twin.

For this tutorial as always (OK, most of the time) I will select the Wi-Fi network “Hack_Me_If_You_Can” as my target.

The tool will prompt you the available phishing scenarios available. For this case, OAuth Login Page attack is available.

The OAuth Login Page attack creates a fake login page asking for credentials of the users who want to connect. Note that while creating a fake access point, it is created as an open network unlike the one we are targeting. I select the OAuth Login Page attack and the attack starts.

So just imagine while we are running this Fake access point, some mobile user is looking for available Wi-Fi networks to connect to. He will see two networks with the same name and gets confused. Once he selects our Evil Twin to connect to, he will be prompted with a login page as shown below.

evil twin attack

Here, he is being asked to submit his Facebook credentials of course by dangling the carrot of free internet. The login page is so believable even to me. And if the user falls for the trick (or carrot) and submits his credentials as shown below.

On Kali Linux, the activity is recorded as shown below.

and the credentials are captured successfully.

That looked simple enough. But where can Evil Twin Attack become successful? In many areas but especially where there are free Wi-Fi access points. Imagine creating an Evil twin with the same name as the original.

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Process Ghosting Explained

Hello aspiring ethical hackers. In this article, you will learn about Process Ghosting, a technique used by hackers to bypass AV/EDR. As soon as an executable file lands on a Windows system, the endpoint Anti Malware opens the file for analysis. After the analysis is complete, the executable starts a process. The Anti Malware routinely detects malicious executables in this manner.

However, there is a small gap of time between the executable launching and the starting of a process. What if the executable is in delete pending state during this time gap? The Anti Malware cannot scan it as the file is in delete-pending state and its later attempts to scan it also fail as the file is already deleted. However, the malicious payload gets executed without being detected. Process Ghosting is a technique used by hackers when creating malware for Windows Operating Systems to avoid detection by Antivirus software including the Windows Defender. This technique takes advantage of a gap between process creation and when Antivirus software is notified of the process creation. This gap allows the malware developers a chance to alter the executable before it is scanned by the antivirus software.
Process Ghosting is built on three major techniques (used to evade Antivirus software detection) used by malware developers; They are,

1. Process Herpaderping

In Process herpaderping, an existing file handle is used in order to overwrite executable with decoy PE. Hence it leaves a camouflaged malware on the disk which is different from the actual process which is running.

2. Process Re-Imaging

Process Re-imaging takes advantage of a cache synchronization problem found in the Windows OS kernel. It causes a mismatch between executable file’s path and the reported path for image sections created from the executable. It loads a DLL at a camouflaged malware path, unloads it and then loads it from a new path.

2. Process Doppel-ganging

In this antivirus detection evasion technique, a malware takes advantage of the Windows Transactional NTFS mechanism. The mechanism allows applications to carry file system operations as a single transaction which if rolled back is not visible to the underlying file system.

Now, let us see step by step how to perform process ghosting. In this tutorial, we will use Process Ghosting to make the executable file of mimikatz undetectable by AV /EDR. Mimikatz can be downloaded from here. To perform process ghosting, we will use a tool called KingHamlet tool designed by IkerSaint. It can be downloaded from here.

This is how the process of process ghosting works with any tool.

1. Download the executable file. In this case, mimikatz.exe.
2. Put file to a delete-pending state using NtSetInformationFile(FileDispositionInformation).
3. Write the payload executable to the file. The content isn’t persisted because the file is already delete-pending. The delete-pending state also blocks external file-open attempts.
4. Create an image section for the file.
5. Close the delete-pending handle, deleting the file.
6. Create a process using the image section.
7. Assign process arguments and environment variables.
8. Create a thread to execute in the process.

As you all know, mimikatz is easily detected by Windows Defender as malware. Let’s see the above steps practically. We fire up the King Hamlet tool in Windows to encrypt the executable file. We use the below commands.

kinghamlet.exe <payload.exe> <encryption key>

This will create the encrypted payload named mimikatz.exe.khe as show below.

Then we run another command to run the encrypted payload as a legitimate process.

kinghamlet.exe <encrypted.exe.khe> <encrypt key> <targetfile.exe>

This is to make sure the process runs as a legitimate executable.

This will run mimikatz.exe on the system as shown below.

process ghosting

Now, open Task Manager and see what process is running with ID 336.

In this case, we ran mimikatz.exe as Bandicam.exe. So our payload decoys itself as a Windows Problem Reporting process which is a Windows core process in the Windows Operating System. When we run the encrypted executable using King Hamlet tool, the Windows Defender detects no current malicious activity as shown below.

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ProxyLogon vulnerability : Explained In detail

Hello aspiring ethical hackers. In this article, you will learn about the ProxyLogon vulnerability. ProxyLogon is a vulnerability that impacts the Microsoft Exchange Server. It is estimated that over 2,50,000 Microsoft Exchange Servers were victims of this vulnerability at the time of its detection.

The Proxy Logon vulnerability is related to the four zero day vulnerabilities that were detected in the Exchange Server in December 2020. On December 10, 2020, Orange Tsai, security researcher working in DEVCORE, discovered that attackers can combine some vulnerabilities in the Exchange Server to achieve remote code execution on the target and upload a webshell to it. The four vulnerabilities are,

CVE-2021-26855: SERVER SIDE REQUEST FORGERY

This is a Server-Side Request Forgery (SSRF) vulnerability in the Exchange Server that allows remote attackers to gain admin access once exploited. This can be exploited by sending a specially crafted web request to a vulnerable Exchange Server. The web request contains an XML SOAP payload directed at the Exchange Web Services (EWS) API endpoint. This request bypasses authentication using specially crafted cookies. This vulnerability, combined with the knowledge of a victim’s email address, means the attacker can exfiltrate all emails from the target’s Exchange mailbox.

CVE-2021-26857: REMOTE CODE EXECUTION VULNERABILITY

This is a post-authentication insecure deserialization vulnerability in the Unified Messaging service of an Exchange Server that allows commands to be run with SYSTEM privileges. The SYSTEM account is used by the operating system and services that run under Windows. As readers have seen many times in our Magazine, a SYSTEM account in Windows has full permissions by default. A hacker can either steal credentials or use the above mentioned vulnerability to execute arbitrary commands on a vulnerable Exchange Server in the security context of SYSTEM.

CVE-2021-26858 AND CVE-2021-27065

These two vulnerabilities are post-authentication arbitrary file write vulnerabilities that allow attackers to write files to any path on a vulnerable Exchange Server. A malicious hacker can also exploit the previously mentioned SSRF vulnerability to achieve admin access and then exploit this vulnerability to write web shells to virtual directories (VDirs). These virtual directories are published to the internet by the server’s Internet Information Server (IIS).
IIS is Microsoft’s web server and a dependency that is installed with Exchange Server and provides services for Outlook on the web, previously known as Outlook Web Access (OWA), Outlook Anywhere, ActiveSync, Exchange Web Services, Exchange Control Panel (ECP), the Offline Address Book (OAB) and AutoDiscover.
According to Microsoft, these vulnerabilities were first exploited by HAFNIUM, a Chinese government sponsored APT (Advanced Persistent Threat) but operating out of China. This group is known to install the web shell named China Chopper. As of 12th March 2021, at least 9 other hacker groups exploited these vulnerabilities apart from HAFNIUM. The versions of Exchange Servers vulnerable to these vulnerabilities are,

Exchange Server 2019 < 15.02.0792.010
Exchange Server 2019 < 15.02.0721.013
Exchange Server 2016 < 15.01.2106.013
Exchange Server 2013 < 15.00.1497.012

The exploit is named Proxy Logon as it exploits the proxy architecture and login mechanism in the Exchange Server.

How to detect ProxyLogon vulnerability?

Metasploit has some modules related to these vulnerabilities. Let’s have a look at these modules.

The auxiliary/gather/exchange_proxylogon_collector module exploits the CVE-2021-26855 vulnerability and dumps all the contents of the mailboxes.

The exploit/windows/http/exchange_proxylogon_rce module exploits the CVE-2021-26855 vulnerability to bypass authentication and gain admin access and then writes a arbitrary file to the target using CVE-2021-27065 to achieve remote code execution. All the above mentioned versions are vulnerable by default.

The auxiliary/scanner/http/exchange_proxylogon module checks for the CVE-2021-26855 vulnerability that makes Exchange Servers vulnerable.

Microsoft has released a security update on March 2021 to patch these vulnerabilities in Exchange Server versions mentioned above. Applying these patches will fix these vulnerabilities. As soon as Microsoft released these security updates, hacker groups around the world went on a scanning spree to hunt for unpatched Exchange Servers.

As there was a delay in applying patches, Microsoft also released a one-click mitigation tool that fixed these vulnerabilities in Exchange Servers. Microsoft has also noted that this tool named Microsoft Exchange On-Premises Mitigation Tool (EOMT) is helpful for those organizations that don’t have a dedicated IT security staff. This tool also includes the Microsoft Safety Scanner and an URL Rewrite mitigation for CVE-2021-26855. However, it stressed that this tool was not an alternative for applying the released security patches.

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Setup Vulhub Lab For hacking practice

Hello aspiring ethical hackers. In this article you will learn how to setup a Vulhub lab for pen testing practice. Getting instances of vulnerable software is one of the most important requirement for practicing penetration testing. Vulhub provides an open-source collection of pre-built vulnerable docker environments. The best thing about Vulhub is that readers don’t need any pre-existing knowledge of dockers and their operation. The only requirement is Docker should already be installed on the system to be able to use Vulhub.

Let’s see how to setup Vulhub Lab. We will do this in Kali Linux on which we already installed Docker earlier. In Kali Linux, open a Terminal and use wget or Git to download the zip archive of Vulhub as shown below.

Once the download is finished, extract the contents of the vulhub-master.zip using unzip command.

This will create a new directory named vulhub-master.

Start the Docker service.

Once the Docker service is started, navigate into the vulhub-master directory and you should see many vulnerable docker images.

vulhub

Let’s start the WordPress Docker container for testing. Although this container is vulnerable with a different vulnerability, we will use it for showing exploitation of a different vulnerability. Navigate into the WordPress directory and start the docker container as shown below.

Once the container is started, use command “docker ps” to see all the docker processes running

Every docker container has a container ID. The one with container ID 2522cc4********* is our WordPress docker container. We can use command “docker inspect <container id>” to get more information about the particular Docker container.

The IP address of the WordPress Docker container is 172.22.0.3. The Gateway address is that of the Kali host machine (172.22.0.1). Enter the IP address of the docker container in the browser and you will be prompted to set the password for the WordPress instance.

Here is the WordPress website we just created (we wanted to set the site title as docker test but misspelled it to docket test).

Go to Exploit Database and download the vulnerable wp-responsive-thumbnail-slider plugin. The plan is to install this vulnerable plugin in WordPress.

Login into the WordPress dashboard with the credentials you set up.

Upload the plugin and activate it.

Now, start Metasploit and load the wp_responsive_thumbnail_slider_upload module.

Set the docker container IP address (172.22.0.3) and check if the target is vulnerable.

The “check” command confirms that the target is indeed vulnerable. It’s time to exploit it. Set the LHOST option to the IP address of the gateway (172.22.0.1). Set the WPusername and WPpassword options to the credentials you have set in the beginning and then execute the module.

The target we set on docker is exploited successfully. The Vulhub Lab we set up is working successfully.

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Understanding Wireless Security : Part 2

Hello aspiring ethical hackers. Welcome to the second part of understanding Wireless security. In Part 1, readers have learnt about the history of WiFi, terminology used in WiFi and WEP security and its weakness. So, let’s continue from there. Responding to the serious weaknesses in WEP encryption security, the Wi-Fi Alliance introduced Wi-Fi Protected Access (WPA) to secure wireless networks. However, the Wi-Fi Alliance intended WPA as an interim measure to take the place of WEP before they bring in Wi-Fi Protected Access 2 (WPA 2).

Wi – Fi Protected Access (WPA)

Also known as Temporal Key Integrity Protocol (TKIP) standard, WPA implements the TKIP encryption method and was introduced in 2003. TKIP introduced three new methods to overcome weaknesses in Wired Equivalent Privacy (WEP) standard.

1. TKIP implements a key mixing function that combines the secret root key with the initialization vector before passing it to the RC4 cipher initialization. WEP on the other hand merely concatenated the initialization vectors to the root key and passed this value to the RC4 cipher.

2. A sequence counter is implemented to protect against replay attacks. Hence, packets received out of order will be rejected by the Access point.

3.TKIP implements a 64-bit Message Integrity Check (MIC) replacing Cyclic Redundancy Check (CRC) used in WEP. This re-initializes the sequence number each time when a new key (Temporal Key) is used.

Wi – Fi Protected Access (WPA) 2

WPA 2 was introduced in 2004 to replace WPA. It implemented the mandatory elements of IEEE 802.11i. 802.11i makes use of the Advanced Encryption Standard (AES) block cipher instead of RC4 stream cipher used by both WEP and WPA. It also uses Counter Mode Cipher Block Chaining Message Authentication Code Protocol (CCMP) encryption protocol. It provides the following security services.

1. Data Confidentiality: It ensures only authorized parties can access the information

2. Authentication: provides proof of genuineness of the user

3. Access control in conjunction with layer management.

Wi – Fi Protected Access 3 (WPA 3)

The Wi-Fi Alliance announced WPA3 as a replacement to WPA2 in 2018. The new standard uses an equivalent 192-bit cryptographic strength in WPA3-Enterprise mode (AES-256 in GCM mode with SHA-384 as HMAC) and still mandates the use of CCMP-128 (AES-128 in CCM mode) as the minimum encryption algorithm in WPA3-Personal mode.
The WPA3 standard also replaces the pre-shared key (PSK) exchange with Simultaneous authentication of Equals (SAE) exchange, a method originally introduced with IEEE 802.11s. This results in a more secure initial key exchange in personal mode and forward secrecy.

WPA – Versions

There are two versions of WPA. They are,

  • A. WPA- Personal
  • B. WPA – Enterprise

WPA – Personal

Wi-Fi Protected Access (WPA) – Personal is designed for home and small office networks. This version uses Pre- Shared Key (PSK) and hence it is also referred as WPA-PSK (pre-shared key) mode. The network traffic is encrypted using a 128-bit encryption key derived from a 256-bit shared key. WPA-Personal mode is available on all three WPA versions.

WPA – Enterprise

As its name implies, this is designed for enterprise networks and requires a RADIUS authentication server. This requires a more complicated setup but provides additional security like protection against dictionary attacks on short passwords. Various kinds of the Extensible Authentication Protocol (EAP) are used for authentication. WPA-Enterprise mode is available on all three WPA versions.

Weakness Of WPA/WPA2

1. Pre-shared key WPA and WPA2 remain vulnerable to password cracking attacks if users rely on a weak password or passphrase.

2. WPA passphrase hashes are seeded from the SSID name and its length; rainbow tables exist for the top 1,000 network SSIDs and a multitude of common passwords, requiring only a quick lookup to speed up cracking WPA-PSK

Brute forcing of simple passwords can be attempted using the Aircrack Suite starting from the four-way authentication handshake exchanged during association or periodic re-authentication. In this article, readers have seen how WPA password was cracked. One important feature of cracking WPA /WPA2 is that we don’t need a lot of traffic to crack it. We just need one client connected to the Wi-Fi Access point. Then we de authenticate it from the Wi-Fi Access point. The client automatically tries to connect to the Wi-Fi access point again.

It is at this stage, we try to capture the WPA handshake. If you have noticed, while using aircrack, to crack the password, we supplied a dictionary or wordlist. While cracking WEP we didn’t.

So what is a weak password? Any password that is part of a dictionary or wordlist can be called a weak password in WPA. Otherwise, WPA /WPA2 is considered secure. WPA3 replaces cryptographic protocols susceptible to off-line analysis with protocols that require interaction with the infrastructure for each guessed password, supposedly placing temporal limits on the number of guesses. However, design flaws in WPA3 enable attackers to plausibly launch brute-force attacks.

Wi-Fi Protected Setup (WPS)

In year 2007, the Wi-Fi Alliance introduced Wi-Fi Protected Setup (WPS). The main feature of this protocol is to allow home users who have little knowledge about wireless security to set up Wi-Fi Protected Access (For some users, accessing the router dashboard and setting passwords can be too complex). It also makes it easy to add new devices to an existing Wireless network without entering long passphrases. WPS also allows the owner of Wi-Fi privileges to block other users from using their household Wi-Fi. There are two common methods to use WPS.

  • PIN Method.
  • Push Button Method.

PIN Method

Every Wireless Router with WPS enabled has a PIN on the Wi-Fi Router (which is usually printed on a sticker). This PIN must then be entered into any new device that wants to connect to this Wireless network. No need of memorizing any password.

Push Button Method

In this method, the user has to PUSH a WPS button on both the Access point and the new wireless client device. On most devices, this discovery mode turns itself off as soon as a connection is established or after a delay (typically 2 minutes or less), whichever comes first, thereby minimizing its vulnerability.
Although WPS was introduced to simplify Wi-Fi Connection issues, it suffers from a major vulnerability. Any remote attacker can recover the WPS pin in a few hours by using brute force attack. Once he does this, he can easily recover WPA/WPA2 key also. Nowadays, all recent models of Wireless Routers have WPS enabled by default. It is wise to turn off WPS PIN feature although this is not possible on many routers.
WPS is widely understood to have added insecurity to otherwise secure WPA/WPA2. WPS pin is a 8 digit PIN that is required by clients to connect to the Wireless Router. The Wireless Router instead of checking the entire 8 digit PIN at once, checks the first four digits initially and then checks the last four digits. This makes brute forcing WPS PINs very easy.
This is because there are only 11,000 possible 4 digit pins and once the brute force software gets the first 4 digit pin right, the attacker can move on to cracking the latter 4 digit pin.
Tools Bully and Reaver are first to come to mind when we want to crack WPS pin. However, in our latest tests, both the tools are presenting some problems. You can read our previous articles on Bully and Wifite.

That was a complete guide to understanding wireless security. Hope our readers now have a better understanding of Wireless security. You can read Part 1 of Understanding Wireless security here. Happy hacking.