Signal App Crypto Cracked, claims Cellebrite

The Signal app has been hacked – its end-to-end encryption is broken. At least, that’s the absurd claim made by notorious forensic vendor Cellebrite.

But the old maxim still applies: No matter how good your tech is, if your opponent controls the physical device, it is game over.

Moxie Marlinspike honcho signal (pictured) will not be a happy bunny. In today’s SB Blogwatch, let’s get physical.

Your humble blog watcher has curated these blogging pieces for you to enjoy. Not to mention the jazz songs.


What is the craic? Omer Benjakob and Oded Yaron report: “The company claims it can now enter the encrypted signal app”:

Cellebrite can now enter Signal, an encrypted app considered safe from outside snoopers, he said. … Cellebrite’s hacking technology is aimed at law enforcement. … However, critics have long criticized the company for selling its products to states with poor human rights records.

Cellebrite’s flagship product is UFED (Universal Forensic Extraction Device), a system that allows authorities to unlock and access the data of any phone in their possession. … The company announced that the analyzer [now] allows clients to decode information and data from Signal.

In an earlier, now deleted, version of the blog post, the company went so far as to say, “Decrypting Signal messages and attachments was no easy task. Extensive research was needed on many different fronts to create new features from scratch. ” [It] it included a detailed explanation of how Cellebrite “cracked the code”: examining Signal’s open source protocol and using it against it.

Cellebrite is currently not subject to independent supervision. Conducts its own exams and maintains its own blacklist of countries to which it is “forbidden” to sell technology, [said] sources with knowledge of the company.

IS Nick Farrell adds: “Cellebrite claims to be able to join Signal”:

Signal, owned by the Signal Technology Foundation, uses [an] encryption system called Signal Protocol, which was thought to make it nearly impossible for a third party to enter a conversation or access data shared on the platform. It does this by using end-to-end encryption.

According to Cellebrite’s announcement last week, “Law enforcement is seeing a rapid increase in the adoption of highly encrypted apps like Signal, which incorporate capabilities … to prevent police from examining your data. … In one Previous, now deleted, version of the blog post, the company said, “Decrypting Signal messages and attachments was not easy. It required extensive research on many different fronts.”

As well as? Cellebrite’s Alon Ganor wrote this way, before the company tore off the juicy pieces: “Cellebrite’s New Solution”:

Signal keeps its database encrypted using SqlScipher, so reading requires a key. We found that capturing the key requires reading a value from the shared preferences file and decrypting it using a key called “AndroidSecretKey”, which is saved by an Android function called “Keystore”.

We simply ran SqlCipher on the database with the decrypted key and the values ​​4096 and 1 for the page size and kdf iterations. In this way we were able to decrypt the database. … Linking messages and attachments requires analyzing both the “sms” table and another table called “part”.

After linking the attached files and messages, we found that the attachments are also encrypted. … We looked at the shared preferences file again and found a value in “pref_attachment_encrypted_secret” which contains the “date” and “iv” fields. The “data” field contains an encrypted json file, which … contains three keys. … Signal uses AES encryption in CTR mode. We used our decryption key with AES encryption in CTR mode and decrypted the attached files.

But we support our valiant law enforcement officers, right? Tom McKay and Dhruv Mehrotra expand the story: “Schools are buying technology to hack phones”:

These invasive phone cracking tools aren’t just bought by police departments. … School districts have been quietly purchasing these surveillance tools for years.

In March 2020, the North East Independent School District, a largely Hispanic district north of San Antonio, wrote Cellebrite a check for $ 6,695 for “General Supplies.” … Similar accounting records from eight school districts, seven of them in Texas, [show] that administrators paid up to $ 11,582 for the controversial surveillance technology. … Together, the districts comprise hundreds of schools, potentially exposing hundreds of thousands of students to invasive cell phone searches.

In [1985] the US Supreme Court ruled that schools do not necessarily need a warrant to search students as long as officials have a reasonable belief that a student has broken the law or school policy. … Mobile phones are deeply personal items and it’s easy to imagine how embarrassing and potentially catastrophic it would be if an administrator or school resource manager used Cellebrite to download private text messages, photos, social media posts, location history and more yet .

Definitely, [we] raised more questions than answers. … Who is subject to this research and who carries it out? How many students searched for their devices and what were the circumstances? Have students or their parents ever been asked to give any kind of meaningful consent, or even informed of phone searches in the first place? What is done with the data next?

Will this keep people away from Signal? Not on your Nellie, says BAReFO0t:

Make no mistake, Moxie will take care of all of this and fix it ASAP, if it’s not just a lie for them backdoor the Android it runs on, like everyone else would. … I don’t see how they could have broken the perfect forward secret, unless the underlying encryption or key exchange was breached. And that would have * much * bigger implications than just Signal.

So None.This puts an unspecified foreign accent:

The cards please.

Welcome to the era of fascism. You’re not actually guilty of anything, but we’ll check your phone to be sure.

Wait. Pause. Ronaldbeal says this is a mountain made of molehill:

Nonsense. … Their claim is that if they have access to your unlocked phone, they can hack into the SQL DB where the old messages are stored and read them.

If me or anyone else has access to your unlocked phone, we could probably just launch the Signal app and see your old messages. Nowhere do they claim to stop messages in transit. A great no burger.

What’s the old maxim? c1ue leads us to:

To be clear: there is no way to protect electronic devices from an attacker with time and money. Phones can be taken apart and their SSDs copied – at that point all you need to know is the software architecture and you can perform parallel cloud attacks against virtual copies.

Meanwhile, PPH is confused:

Why did they announce the capacity? I don’t remember Churchill bragging about breaking Enigma during World War II.

And finally:

“Like that. Damn. Groovy.”

Trigger alerts: Gurning drummer, semiquavers, Doctor Who.

Previously in And finally

You have read SB Blogwatch by Richi Jennings. Richi curates the best blogging bits, the best forums, and the weirdest websites … so you don’t have to. Hate speech mail can be addressed to @RiCHi or [email protected] Ask your doctor before reading. Your mileage may vary. E&OE. 30.

Salsa image: John S. and James L. Knight Foundation (cc: by-sa)