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Supply-Chain Attack against the Electron Development Platform

Electron is a cross-platform development system for many popular communications apps, including Skype, Slack, and WhatsApp. Security vulnerabilities in the update system allows someone to silently inject malicious code into applications. From a news article:

At the BSides LV security conference on Tuesday, Pavel Tsakalidis demonstrated a tool he created called BEEMKA, a Python-based tool that allows someone to unpack Electron ASAR archive files and inject new code into Electron’s JavaScript libraries and built-in Chrome browser extensions. The vulnerability is not part of the applications themselves but of the underlying Electron framework—­and that vulnerability allows malicious activities to be hidden within processes that appear to be benign. Tsakalidis said that he had contacted Electron about the vulnerability but that he had gotten no response—­and the vulnerability remains.

While making these changes required administrator access on Linux and MacOS, it only requires local access on Windows. Those modifications can create new event-based “features” that can access the file system, activate a Web cam, and exfiltrate information from systems using the functionality of trusted applications­—including user credentials and sensitive data. In his demonstration, Tsakalidis showed a backdoored version of Microsoft Visual Studio Code that sent the contents of every code tab opened to a remote website.

Basically, the Electron ASAR files aren’t signed or encrypted, so modifying them is easy.

Note that this attack requires local access to the computer, which means that an attacker that could do this could do much more damaging things as well. But once an app has been modified, it can be distributed to other users. It’s not a big deal attack, but it’s a vulnerability that should be closed.

Posted on August 8, 2019 at 11:11 AMView Comments

AT&T Employees Took Bribes to Unlock Smartphones

This wasn’t a small operation:

A Pakistani man bribed AT&T call-center employees to install malware and unauthorized hardware as part of a scheme to fraudulently unlock cell phones, according to the US Department of Justice. Muhammad Fahd, 34, was extradited from Hong Kong to the US on Friday and is being detained pending trial.

An indictment alleges that “Fahd recruited and paid AT&T insiders to use their computer credentials and access to disable AT&T’s proprietary locking software that prevented ineligible phones from being removed from AT&T’s network,” a DOJ announcement yesterday said. “The scheme resulted in millions of phones being removed from AT&T service and/or payment plans, costing the company millions of dollars. Fahd allegedly paid the insiders hundreds of thousands of dollars­—paying one co-conspirator $428,500 over the five-year scheme.”

In all, AT&T insiders received more than $1 million in bribes from Fahd and his co-conspirators, who fraudulently unlocked more than 2 million cell phones, the government alleged. Three former AT&T customer service reps from a call center in Bothell, Washington, already pleaded guilty and agreed to pay the money back to AT&T.

Posted on August 8, 2019 at 6:22 AMView Comments

Brazilian Cell Phone Hack

I know there’s a lot of politics associated with this story, but concentrate on the cybersecurity aspect for a moment. The cell phones of a thousand Brazilians, including senior government officials, were hacked—seemingly by actors much less sophisticated than rival governments.

Brazil’s federal police arrested four people for allegedly hacking 1,000 cellphones belonging to various government officials, including that of President Jair Bolsonaro.

Police detective João Vianey Xavier Filho said the group hacked into the messaging apps of around 1,000 different cellphone numbers, but provided little additional information at a news conference in Brasilia on Wednesday. Cellphones used by Bolsonaro were among those attacked by the group, the justice ministry said in a statement on Thursday, adding that the president was informed of the security breach.

[…]

In the court order determining the arrest of the four suspects, Judge Vallisney de Souza Oliveira wrote that the hackers had accessed Moro’s Telegram messaging app, along with those of two judges and two federal police officers.

When I say that smartphone security equals national security, this is the kind of thing I am talking about.

Posted on August 7, 2019 at 10:48 AMView Comments

Regulating International Trade in Commercial Spyware

Siena Anstis, Ronald J. Deibert, and John Scott-Railton of Citizen Lab published an editorial calling for regulating the international trade in commercial surveillance systems until we can figure out how to curb human rights abuses.

Any regime of rigorous human rights safeguards that would make a meaningful change to this marketplace would require many elements, for instance, compliance with the U.N. Guiding Principles on Business and Human Rights. Corporate tokenism in this space is unacceptable; companies will have to affirmatively choose human rights concerns over growing profits and hiding behind the veneer of national security. Considering the lies that have emerged from within the surveillance industry, self-reported compliance is insufficient; compliance will have to be independently audited and verified and accept robust measures of outside scrutiny.

The purchase of surveillance technology by law enforcement in any state must be transparent and subject to public debate. Further, its use must comply with frameworks setting out the lawful scope of interference with fundamental rights under international human rights law and applicable national laws, such as the “Necessary and Proportionate” principles on the application of human rights to surveillance. Spyware companies like NSO Group have relied on rubber stamp approvals by government agencies whose permission is required to export their technologies abroad. To prevent abuse, export control systems must instead prioritize a reform agenda that focuses on minimizing the negative human rights impacts of surveillance technology and that ensures—with clear and immediate consequences for those who fail—that companies operate in an accountable and transparent environment.

Finally, and critically, states must fulfill their duty to protect individuals against third-party interference with their fundamental rights. With the growth of digital authoritarianism and the alarming consequences that it may hold for the protection of civil liberties around the world, rights-respecting countries need to establish legal regimes that hold companies and states accountable for the deployment of surveillance technology within their borders. Law enforcement and other organizations that seek to protect refugees or other vulnerable persons coming from abroad will also need to take digital threats seriously.

Posted on August 5, 2019 at 9:14 AMView Comments

More on Backdooring (or Not) WhatsApp

Yesterday, I blogged about a Facebook plan to backdoor WhatsApp by adding client-side scanning and filtering. It seems that I was wrong, and there are no such plans.

The only source for that post was a Forbes essay by Kalev Leetaru, which links to a previous Forbes essay by him, which links to a video presentation from a Facebook developers conference.

Leetaru extrapolated a lot out of very little. I watched the video (the relevant section is at the 23:00 mark), and it doesn’t talk about client-side scanning of messages. It doesn’t talk about messaging apps at all. It discusses using AI techniques to find bad content on Facebook, and the difficulties that arise from dynamic content:

So far, we have been keeping this fight [against bad actors and harmful content] on familiar grounds. And that is, we have been training our AI models on the server and making inferences on the server when all the data are flooding into our data centers.

While this works for most scenarios, it is not the ideal setup for some unique integrity challenges. URL masking is one such problem which is very hard to do. We have the traditional way of server-side inference. What is URL masking? Let us imagine that a user sees a link on the app and decides to click on it. When they click on it, Facebook actually logs the URL to crawl it at a later date. But…the publisher can dynamically change the content of the webpage to make it look more legitimate [to Facebook]. But then our users click on the same link, they see something completely different—oftentimes it is disturbing; oftentimes it violates our policy standards. Of course, this creates a bad experience for our community that we would like to avoid. This and similar integrity problems are best solved with AI on the device.

That might be true, but it also would hand whatever secret-AI sauce Facebook has to every one of its users to reverse engineer—which means it’s probably not going to happen. And it is a dumb idea, for reasons Steve Bellovin has pointed out.

Facebook’s first published response was a comment on the Hacker News website from a user named “wcathcart,” which Cardozo assures me is Will Cathcart, the vice president of WhatsApp. (I have no reason to doubt his identity, but surely there is a more official news channel that Facebook could have chosen to use if they wanted to.) Cathcart wrote:

We haven’t added a backdoor to WhatsApp. The Forbes contributor referred to a technical talk about client side AI in general to conclude that we might do client side scanning of content on WhatsApp for anti-abuse purposes.

To be crystal clear, we have not done this, have zero plans to do so, and if we ever did it would be quite obvious and detectable that we had done it. We understand the serious concerns this type of approach would raise which is why we are opposed to it.

Facebook’s second published response was a comment on my original blog post, which has been confirmed to me by the WhatsApp people as authentic. It’s more of the same.

So, this was a false alarm. And, to be fair, Alec Muffet called foul on the first Forbes piece:

So, here’s my pre-emptive finger wag: Civil Society’s pack mentality can make us our own worst enemies. If we go around repeating one man’s Germanic conspiracy theory, we may doom ourselves to precisely what we fear. Instead, we should ­ we must ­ take steps to constructively demand what we actually want: End to End Encryption which is worthy of the name.

Blame accepted. But in general, this is the sort of thing we need to watch for. End-to-end encryption only secures data in transit. The data has to be in the clear on the device where it is created, and it has to be in the clear on the device where it is consumed. Those are the obvious places for an eavesdropper to get a copy.

This has been a long process. Facebook desperately wanted to convince me to correct the record, while at the same time not wanting to write something on their own letterhead (just a couple of comments, so far). I spoke at length with Privacy Policy Manager Nate Cardozo, whom Facebook hired last December from EFF. (Back then, I remember thinking of him—and the two other new privacy hires—as basically human warrant canaries. If they ever leave Facebook under non-obvious circumstances, we know that things are bad.) He basically leveraged his historical reputation to assure me that WhatsApp, and Facebook in general, would never do something like this. I am trusting him, while also reminding everyone that Facebook has broken so many privacy promises that they really can’t be trusted.

Final note: If they want to be trusted, Adam Shostack and I gave them a road map.

Hacker News thread.

EDITED TO ADD (8/4): Slashdot covered my retraction.

Posted on August 2, 2019 at 2:18 PMView Comments

How Privacy Laws Hurt Defendants

Rebecca Wexler has an interesting op-ed about an inadvertent harm that privacy laws can cause: while law enforcement can often access third-party data to aid in prosecution, the accused don’t have the same level of access to aid in their defense:

The proposed privacy laws would make this situation worse. Lawmakers may not have set out to make the criminal process even more unfair, but the unjust result is not surprising. When lawmakers propose privacy bills to protect sensitive information, law enforcement agencies lobby for exceptions so they can continue to access the information. Few lobby for the accused to have similar rights. Just as the privacy interests of poor, minority and heavily policed communities are often ignored in the lawmaking process, so too are the interests of criminal defendants, many from those same communities.

In criminal cases, both the prosecution and the accused have a right to subpoena evidence so that juries can hear both sides of the case. The new privacy bills need to ensure that law enforcement and defense investigators operate under the same rules when they subpoena digital data. If lawmakers believe otherwise, they should have to explain and justify that view.

For more detail, see her paper.

Posted on August 2, 2019 at 6:04 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.