Attack on SSL Users Discovered, Tool Sources Released
SSL won't come to a rest: the newest attack isn't about encryption or errors in the Secure Sockets Layer protocol, it's about the weakest link in the chain -- the user.
Moxie Marlinspike had already developed sslsniff in 2002. Based on certificate chaining, the client proxy tool intercepts HTTPS traffic from the server and switches the certificate with its own. Assuming a correct configuration and current browser, the result of its use removes any associated attack opportunities. But, asks Marlinspike, what if the client browser doesn't do any SSL queries?
That's why the San Franciscan developed a further proxy named sslstrip (see his presentation slides). The sslstrip tool searches for embedded links, such as https://.../login.php, originating from server webpages and replaces all HTTPS links with like-named HTTP links, such as http://.../login.php, while remembering the original HTTPS target. When the user clicks the modified URL, the sslstrip proxy recognizes it and opens an SSL connection with the server, which sends the webpage, albeit over a nonsecure connection.
In this way the man-in-the-middle (MITM) attacker can access all information from the connection. Such a scenario has an obvious application for online banking where only an HTTP start page might appear, but with visible SSL links and icons that give at least a visual sense of security. Often users ignore warning dialogs and click through them. In the case of an sslstrip intervention, the user doesn't even get the warning dialogs, because no apparent invalid HTTPS connection is created. His browser simply doesn't create a secure connection. The kind of MITM attacks this can provide, and how users might be totally unaware of them, is clearly indicated in Marlinspike's "New Tricks for Defeating SSL in Practice" slides.
After some wide-ranging debate last week about sslstrip, the tool is now available for download. It comprises about 1,000 lines of Python code and is under GLPv3 licensing.
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
Kali Linux 2025.3 Released with New Hacking Tools
If you're a Kali Linux fan, you'll be glad to know that the third release of this famous pen-testing distribution is now available with updates for key components.
-
Zorin OS 18 Beta Available for Testing
The latest release from the team behind Zorin OS is ready for public testing, and it includes plenty of improvements to make it more powerful, user-friendly, and productive.
-
Fedora Linux 43 Beta Now Available for Testing
Fedora Linux 43 Beta ships with Gnome 49 and KDE Plasma 6.4 (and other goodies).
-
USB4 Maintainer Leaves Intel
Michael Jamet, one of the primary maintainers of USB4 and Thunderbolt drivers, has left Intel, leaving a gaping hole for the Linux community to deal with.
-
Budgie 10.9.3 Now Available
The latest version of this elegant and configurable Linux desktop aligns with changes in Gnome 49.
-
KDE Linux Alpha Available for Daring Users
It's official, KDE Linux has arrived, but it's not quite ready for prime time.
-
AMD Initiates Graphics Driver Updates for Linux Kernel 6.18
This new AMD update focuses on power management, display handling, and hardware support for Radeon GPUs.
-
AerynOS Alpha Release Available
With a choice of several desktop environments, AerynOS 2025.08 is almost ready to be your next operating system.
-
AUR Repository Still Under DDoS Attack
Arch User Repository continues to be under a DDoS attack that has been going on for more than two weeks.
-
RingReaper Malware Poses Danger to Linux Systems
A new kind of malware exploits modern Linux kernels for I/O operations.