How to use the command 'sslstrip' (with examples)

sslstrip is a command-line tool designed to intercept and manipulate Secure Sockets Layer (SSL) and Transport Layer Security (TLS) encrypted traffic. Developed by Moxie Marlinspike, the tool performs what’s known as an SSL stripping attack, a man-in-the-middle attack that converts secure HTTPS traffic into unsecured HTTP traffic without users noticing. By doing this, it’s possible to log sensitive information, such as passwords or other data sent through forms on a website. Typically, this is used in combination with ARP spoofing to reroute traffic through the attacker’s machine. It’s crucial to remember that sslstrip is intended for educational and penetration testing purposes in strictly ethical scenarios.

Use case 1: Log only HTTPS POST traffic on port 10000 by default

Code:

sslstrip

Motivation: This basic invocation of sslstrip is useful when you want to capture simple HTTPS POST requests without targeting a specific port. It listens on port 10000 by default, which is sufficient for testing or learning purposes where default configurations are adequate.

Explanation:

• Running sslstrip without any additional arguments will automatically initiate the tool to listen for HTTPS POST traffic on port 10000. POST requests often contain sensitive information submitted through forms, making this a crucial flow to monitor for understanding potential vulnerabilities.

Example Output:

sslstrip output is printed on the console
[30/Nov/2009 14:12:49] INFO: Running with SSL listen socket.
...

Use case 2: Log only HTTPS POST traffic on port 8080

Code:

sslstrip --listen=8080

Motivation: Changing the listening port to 8080 or any other port is useful when operating in an environment where the default port 10000 is occupied or monitored, or when integrating into an existing test setup that uses specified ports for traffic routing.

Explanation:

• --listen=8080: This argument instructs sslstrip to focus on port 8080, ignoring the default port. This flexibility is handy in complex network setups or when simulating real-life scenarios.

Example Output:

sslstrip logging HTTPS POST traffic on port 8080
[30/Nov/2009 14:12:49] INFO: Running on port 8080.
...

Use case 3: Log all SSL traffic to and from the server on port 8080

Code:

sslstrip --ssl --listen=8080

Motivation: This command is essential when you want to capture and log all SSL traffic without limiting it to POST requests, providing broader surveillance and insight into the data being exchanged over SSL/TLS with more granularity.

Explanation:

• --ssl: Instructs sslstrip to capture all SSL traffic, not just POST requests, which might include GET requests or other SSL/TLS traffic.
• --listen=8080: Direct the tool to listen on a specified port (8080 in this case).

Example Output:

sslstrip logging all SSL traffic on port 8080
[30/Nov/2009 14:13:24] INFO: SSL logging active.
...

Use case 4: Log all SSL and HTTP traffic to and from the server on port 8080

Code:

sslstrip --listen=8080 --all

Motivation: This configuration allows comprehensive logging of both encrypted SSL and unencrypted HTTP traffic. It’s useful for comprehensive analysis from both secure and non-secure data channels, and provides a clear picture of all the traffic traversing the network.

Explanation:

• --listen=8080: Sets up the interface on port 8080.
• --all: Ensures that not only SSL traffic but also HTTP traffic is captured, extending surveillance to capture potentially overlooked unsecure data exchanges.

Example Output:

sslstrip logging all SSL and HTTP traffic on port 8080
[30/Nov/2009 14:20:01] INFO: Capture all SSL and HTTP traffic.
...

Use case 5: Specify the file path to store the logs

Code:

sslstrip --listen=8080 --write=path/to/file

Motivation: Saving the log data to a file is critical for analysis after a test or audit. By specifying a file path, you ensure that logs are stored securely for later inspection and are not just available in the current session output.

Explanation:

• --listen=8080: As before, specifies the network port for sslstrip to focus on.
• --write=path/to/file: Directs sslstrip to write logs of intercepted traffic to the specified directory path, providing a persistent record of captured traffic.

Example Output:

sslstrip writing logs to /path/to/file
[30/Nov/2009 14:25:37] INFO: Logs being written to /path/to/file
...

Use case 6: Display help

Code:

sslstrip --help

Motivation: Invoking the help option is crucial for users who are new to sslstrip or need a reminder of available commands and their framework. This can guide users on how to correctly implement various options and arguments.

Explanation:

• --help: This argument produces a summary of all commands and options sslstrip offers, displaying how each might be used within the tool.

Example Output:

sslstrip version X.X
Usage: sslstrip [options]
...

Conclusion

Understanding the various functionalities and use cases of the sslstrip command allows security professionals and enthusiasts to simulate real-world environment attacks. When used responsibly and ethically, sslstrip provides valuable insights into network security weaknesses and strengthens one’s penetration-testing toolkit.