DNS-over-HTTPS Is The Wrong Partial Solution

October 21, 2019 by Maya Posch 51 Comments

Openness has been one of the defining characteristics of the Internet for as long as it has existed, with much of the traffic today still passed without any form of encryption. Most requests for HTML pages and associated content are in plain text, and the responses are returned in the same way, even though HTTPS has been around since 1994.

But sometimes there’s a need for security and/or privacy. While the encryption of internet traffic has become more widespread for online banking, shopping, the privacy-preserving aspect of many internet protocols hasn’t kept pace. In particular, when you look up a website’s IP address by hostname, the DNS request is almost always transmitted in plain text, allowing all the computers and ISPs along the way to determine what website you were browsing, even if you use HTTPS once the connection is made.

The idea of also encrypting DNS requests isn’t exactly new, with the first attempts starting in the early 2000s, in the form of DNSCrypt, DNS over TLS (DoT), and others. Mozilla, Google, and a few other large internet companies are pushing a new method to encrypt DNS requests: DNS over HTTPS (DoH).

DoH not only encrypts the DNS request, but it also serves it to a “normal” web server rather than a DNS server, making the DNS request traffic essentially indistinguishable from normal HTTPS. This is a double-edged sword. While it protects the DNS request itself, just as DNSCrypt or DoT do, it also makes it impossible for the folks in charge of security at large firms to monitor DNS spoofing and it moves the responsibility for a critical networking function from the operating system into an application. It also doesn’t do anything to hide the IP address of the website that you just looked up — you still go to visit it, after all.

And in comparison to DoT, DoH centralizes information about your browsing in a few companies: at the moment Cloudflare, who says they will throw your data away within 24 hours, and Google, who seems intent on retaining and monetizing every detail about everything you’ve ever thought about doing.

DNS and privacy are important topics, so we’re going to dig into the details here. Continue reading “DNS-over-HTTPS Is The Wrong Partial Solution” →

File Compression By Steganography

October 19, 2019 by Sharon Lin 29 Comments

In a world with finite storage and an infinite need for more storage space, data compression becomes a very necessary problem. Several algorithms for data compression may be more familiar – Huffman coding, LZW compression – and some a bit more arcane.

[Labunsky] decided to put to use his knowledge of steganography to create a wholly unique form of file compression, perhaps one that may gain greater notoriety among other information theorists.

Steganography refers to the method of concealing messages or files within another file, coming from the Greek words steganos for “covered or concealed” and graphe for “writing”. The practice has been around for ages, from writing in invisible ink to storing messages in moon cakes. The methods used range from hiding messages in images to evade censorship to hiding viruses in files to cause mayhem.

The developer explains that since every file is just a bit sequence, observing files leads to the realization that a majority of bits will be equal on the same places. Rather than storing all of the bits of a file, making modifications to the hard drive at certain locations can save storage space. What is important to avoid, however, is lossy file compression that can wreak havoc on quality during the compression stage.

The compression technique they ended up implementing is based on the F5 algorithm that embeds binary data into JPEG files to reduce total space in the memory. The compression uses libjpeg for JPEG decoding and encoding, pcre for POSIX regular expressions support, and tinydir for platform-independent filesystem traversal. One of the major modifications was to save computation resources by disabling a password-based permutative straddling that uniformly spreads data among multiple files.

One caveat – changing even one bit of the compressed file could lead to total corruption of all of the data stored, so use with caution!

Revisiting The BlackHat Hack: How A Security Conference Was Pwned

October 18, 2019 by Sharon Lin 1 Comment

Does anyone remember the Black Hat BCard hack in 2018? This hack has been documented extensively, most notoriously by [NinjaStyle] in his original blog post revealing the circumstances around discovering the vulnerability. The breach ended up revealing the names, email addresses, phone numbers, and personal details of every single conference attendee – an embarrassing leak from one of the world’s largest cybersecurity conferences.

To recap: The Black Hat conference badges included an embedded NFC tag storing the participant’s contact details presumably for vendors to scan for marketing purposes. After scanning the tag, [NinjaStyle] realized that his name was readily available, but not his email address and other information. Instead, the NFC reader pointed to the BCard app – an application created for reading business cards.

[NinjaStyle] decompiled the APK for the app to search for API endpoints and found that the participants each had a custom URL made using event identification values. After finding data that appeared to correspond to an eventID and badgeID, he sent a request over a web browser and found that his attendee data was returned completely unauthenticated. With this knowledge, it was possible to brute-force the contact details for every Black Hat attendee (the range of valid IDs was between 100000-999999, and there were about 18,000 attendees). Using Burp Suite, the task would take about six hours.

He was able to get ahold of BCard to reveal the vulnerability, which was fixed in less than a day by disabling the leaky API from their legacy system. Even so, legacy APIs in conference apps aren’t an uncommon occurrence – the 2018 RSA Conference (another cybersecurity conference) also suffered from an unprotected app that allowed 114 attendee records to be accessed without permission.

With the widespread publicity of leaked attendee data, event organizers are hopefully getting smarter about the apps that they use, especially if they come from a third-party vendor. [Yashvier Kosaraju] gave a talk at TROOPERS19 about pen testing several large vendors and discovering that Kitapps (Attendify) and Eventmobi both built apps with unauthenticated access to attendee data. It’s hard to say how many apps from previous years are still around, or whether or not the next event app you use will come with authentication – just remember to stay vigilant and to not give too much of your personal data away.

This Week In Security: A Digital Café Américain, The Linux Bugs That Weren’t, The Great Nation, And More

October 18, 2019 by Jonathan Bennett 16 Comments

A government is going after a human rights activists in Morocco. It sounds familiar, but I don’t think Humphrey Bogart is running the gin joint this time around.

Questionable Casablanca references aside, Amnesty International has reported another attack against human rights workers. In this case, a pair of Moroccan activists were targeted with what appears to be NSO’s Pegasus malware suite. Researchers identified text message phishing that led to malicious web pages, as well as HTTP man in the middle attacks against their mobile devices. Once the target was successfully directed to the malicious site, A collection of zero-day vulnerabilities were used to compromise the phone with the NSO malware.

NSO is an Israeli company that specializes in building malware and other cybersecurity tools for governments. As you can imagine, this specialization has earned NSO the scorn of quite a few organizations. NSO claims to have a policy framework in place that allows them to evaluate and terminate the use of their software when it is deemed illegal or abusive, but due to the nature of their contracts, that process is anything but transparent. Continue reading “This Week In Security: A Digital Café Américain, The Linux Bugs That Weren’t, The Great Nation, And More” →

A Tamagotchi For WiFi Cracking

October 16, 2019 by Bryan Cockfield 8 Comments

OK, let’s start this one by saying that it’s useful to know how to break security measures in order to understand how to better defend yourself, and that you shouldn’t break into any network you don’t have access to. That being said, if you want to learn about security and the weaknesses within the WPA standard, there’s no better way to do it than with a tool that mimics the behavior of a Tamagotchi.

Called the pwnagotchi, this package of artificial intelligence looks for information in local WiFi packets that can be used to crack WPA encryption. It’s able to modify itself in order to maximize the amount of useful information it’s able to obtain from whatever environment you happen to place it in. As an interesting design choice, the pwnagotchi behaves like an old Tamagotchi pet would, acting happy when it gets the inputs it needs.

This project is beyond a novelty though and goes deep in the weeds of network security. If you’re at all interested in the ways in which your own networks might be at risk, this might be a tool you can use to learn a little more about the ways of encryption, general security, and AI to boot. Of course, if you’re new to the network security world, make sure the networks you’re using are secured at least a little bit first.

Thanks to [Itay] for the tip!

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October 10, 2019 by Sharon Lin 22 Comments

Some sentences have more than meets the eye, and we’re not talking about interpretive nonsense. Rather, some sentences may contain up to four paragraphs’ worth of hidden text, invisible to readers.

Thanks to Zero Width Obfuscation, it is possible to use Zero Width Characters – Unicode characters that are invisible even when you try to highlight them. They’re typically used for abstract foreign languages that require separators that don’t take up an entire space. In this case, they’re used to obfuscate and de-obfuscate hidden messages sent through text.

[inzerosight] published a browser extension that identifies, de-obfuscates, and obfuscates these messages for you on the web. It does this by querying each page for the Unicode of the Zero Width Characters (U+FEFF, U+200C, U+200D, U+200E, U+2060, U+180E) and highlighting where they’ve been spotted. The encoding replaces each Unicode character with a permutation of two of the Zero Width Characters, essentially doing a find and replace across the text message.

I’m just waiting to see how long it takes for Zero Width Obfuscation to become the next Konami Code Easter Egg.

This Week In Security: Is RSA Finally Broken? The Push For Cloud Accounts, Encrypted DNS, And More Mobile Mayhem

October 4, 2019 by Jonathan Bennett 24 Comments

Ever wondered what “cyberwar” looks like? Apparently it’s a lot of guessing security questions and changing passwords. It’s an interesting read on its own, but there are some interesting clues if you read between the lines. A General in the know mentioned that Isis:

clicked on something or they did something that then allowed us to gain control and then start to move.

This sounds very similar to stories we’ve covered in the past, where 0-days are used to compromise groups or individuals. Perhaps the NSA supplied such an exploit, and it was sent in a phishing attack. Through various means, the U.S. team quietly compromised systems and collected credentials.

The article mentions something else interesting. Apparently the targets of this digital sting had also been compromising machines around the world, and using those machines to manage their efforts. The decision was made by the U.S. team to also compromise those machines, in order to lock out the Isis team. This might be the most controversial element of the story. Security researchers have wanted permission to do this for years. How should the third parties view these incursions?

The third element that I found particularly interesting was the phase 2 attack. Rather than outright delete, ban, and break Isis devices and accounts, the U.S. team installed persistent malware that emulated innocuous glitches. The internet connection is extremely laggy on certain days, certain websites simply don’t connect, and other problems. These are the sort of gremlins that networking pros spend all day trying to troubleshoot. The idea that it’s intentional gives me one more thing to worry about. Continue reading “This Week In Security: Is RSA Finally Broken? The Push For Cloud Accounts, Encrypted DNS, And More Mobile Mayhem” →