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Dependency Confusion: Another Supply-Chain Vulnerability

Alex Birsan writes about being able to install malware into proprietary corporate software by naming public code files the same as internal code files. From a ZDNet article:

Today, developers at small or large companies use package managers to download and import libraries that are then assembled together using build tools to create a final app.

This app can be offered to the company’s customers or can be used internally at the company as an employee tool.

But some of these apps can also contain proprietary or highly-sensitive code, depending on their nature. For these apps, companies will often use private libraries that they store inside a private (internal) package repository, hosted inside the company’s own network.

When apps are built, the company’s developers will mix these private libraries with public libraries downloaded from public package portals like npm, PyPI, NuGet, or others.

[…]

Researchers showed that if an attacker learns the names of private libraries used inside a company’s app-building process, they could register these names on public package repositories and upload public libraries that contain malicious code.

The “dependency confusion” attack takes place when developers build their apps inside enterprise environments, and their package manager prioritizes the (malicious) library hosted on the public repository instead of the internal library with the same name.

The research team said they put this discovery to the test by searching for situations where big tech firms accidentally leaked the names of various internal libraries and then registered those same libraries on package repositories like npm, RubyGems, and PyPI.

Using this method, researchers said they successfully loaded their (non-malicious) code inside apps used by 35 major tech firms, including the likes of Apple, Microsoft, PayPal, Shopify, Netflix, Yelp, Uber, and others.

Clever attack, and one that has netted him $130K in bug bounties.

More news articles.

Posted on February 23, 2021 at 6:18 AMView Comments

GPS Vulnerabilities

Really good op-ed in the New York Times about how vulnerable the GPS system is to interference, spoofing, and jamming—and potential alternatives.

The 2018 National Defense Authorization Act included funding for the Departments of Defense, Homeland Security and Transportation to jointly conduct demonstrations of various alternatives to GPS, which were concluded last March. Eleven potential systems were tested, including eLoran, a low-frequency, high-power timing and navigation system transmitted from terrestrial towers at Coast Guard facilities throughout the United States.

“China, Russia, Iran, South Korea and Saudi Arabia all have eLoran systems because they don’t want to be as vulnerable as we are to disruptions of signals from space,” said Dana Goward, the president of the Resilient Navigation and Timing Foundation, a nonprofit that advocates for the implementation of an eLoran backup for GPS.

Also under consideration by federal authorities are timing systems delivered via fiber optic network and satellite systems in a lower orbit than GPS, which therefore have a stronger signal, making them harder to hack. A report on the technologies was submitted to Congress last week.

GPS is a piece of our critical infrastructure that is essential to a lot of the rest of our critical infrastructure. It needs to be more secure.

Posted on February 22, 2021 at 6:17 AMView Comments

Router Security

This report is six months old, and I don’t know anything about the organization that produced it, but it has some alarming data about router security.

Conclusion: Our analysis showed that Linux is the most used OS running on more than 90% of the devices. However, many routers are powered by very old versions of Linux. Most devices are still powered with a 2.6 Linux kernel, which is no longer maintained for many years. This leads to a high number of critical and high severity CVEs affecting these devices.

Since Linux is the most used OS, exploit mitigation techniques could be enabled very easily. Anyhow, they are used quite rarely by most vendors except the NX feature.

A published private key provides no security at all. Nonetheless, all but one vendor spread several private keys in almost all firmware images.

Mirai used hard-coded login credentials to infect thousands of embedded devices in the last years. However, hard-coded credentials can be found in many of the devices and some of them are well known or at least easy crackable.

However, we can tell for sure that the vendors prioritize security differently. AVM does better job than the other vendors regarding most aspects. ASUS and Netgear do a better job in some aspects than D-Link, Linksys, TP-Link and Zyxel.

Additionally, our evaluation showed that large scale automated security analysis of embedded devices is possible today utilizing just open source software. To sum it up, our analysis shows that there is no router without flaws and there is no vendor who does a perfect job regarding all security aspects. Much more effort is needed to make home routers as secure as current desktop of server systems.

One comment on the report:

One-third ship with Linux kernel version 2.6.36 was released in October 2010. You can walk into a store today and buy a brand new router powered by software that’s almost 10 years out of date! This outdated version of the Linux kernel has 233 known security vulnerabilities registered in the Common Vulnerability and Exposures (CVE) database. The average router contains 26 critically-rated security vulnerabilities, according to the study.

We know the reasons for this. Most routers are designed offshore, by third parties, and then private labeled and sold by the vendors you’ve heard of. Engineering teams come together, design and build the router, and then disperse. There’s often no one around to write patches, and most of the time router firmware isn’t even patchable. The way to update your home router is to throw it away and buy a new one.

And this paper demonstrates that even the new ones aren’t likely to be secure.

Posted on February 19, 2021 at 6:00 AMView Comments

Browser Tracking Using Favicons

Interesting research on persistent web tracking using favicons. (For those who don’t know, favicons are those tiny icons that appear in browser tabs next to the page name.)

Abstract: The privacy threats of online tracking have garnered considerable attention in recent years from researchers and practitioners alike. This has resulted in users becoming more privacy-cautious and browser vendors gradually adopting countermeasures to mitigate certain forms of cookie-based and cookie-less tracking. Nonetheless, the complexity and feature-rich nature of modern browsers often lead to the deployment of seemingly innocuous functionality that can be readily abused by adversaries. In this paper we introduce a novel tracking mechanism that misuses a simple yet ubiquitous browser feature: favicons. In more detail, a website can track users across browsing sessions by storing a tracking identifier as a set of entries in the browser’s dedicated favicon cache, where each entry corresponds to a specific subdomain. In subsequent user visits the website can reconstruct the identifier by observing which favicons are requested by the browser while the user is automatically and rapidly redirected through a series of subdomains. More importantly, the caching of favicons in modern browsers exhibits several unique characteristics that render this tracking vector particularly powerful, as it is persistent (not affected by users clearing their browser data), non-destructive (reconstructing the identifier in subsequent visits does not alter the existing combination of cached entries), and even crosses the isolation of the incognito mode. We experimentally evaluate several aspects of our attack, and present a series of optimization techniques that render our attack practical. We find that combining our favicon-based tracking technique with immutable browser-fingerprinting attributes that do not change over time allows a website to reconstruct a 32-bit tracking identifier in 2 seconds. Furthermore,our attack works in all major browsers that use a favicon cache, including Chrome and Safari. Due to the severity of our attack we propose changes to browsers’ favicon caching behavior that can prevent this form of tracking, and have disclosed our findings to browser vendors who are currently exploring appropriate mitigation strategies.

Another researcher has implemented this proof of concept:

Strehle has set up a website that demonstrates how easy it is to track a user online using a favicon. He said it’s for research purposes, has released his source code online, and detailed a lengthy explanation of how supercookies work on his website.

The scariest part of the favicon vulnerability is how easily it bypasses traditional methods people use to keep themselves private online. According to Strehle, the supercookie bypasses the “private” mode of Chrome, Safari, Edge, and Firefox. Clearing your cache, surfing behind a VPN, or using an ad-blocker won’t stop a malicious favicon from tracking you.

EDITED TO ADD (3/12): There was an issue about whether this paper was inappropriately disclosed, and it was briefly deleted from the NDSS website. It was later put back with a prefatory note from the NDSS.

Posted on February 17, 2021 at 6:05 AMView Comments

Malicious Barcode Scanner App

Interesting story about a barcode scanner app that has been pushing malware on to Android phones. The app is called Barcode Scanner. It’s been around since 2017 and is owned by the Ukrainian company Lavabird Ldt. But a December 2020 update included some new features:

However, a rash of malicious activity was recently traced back to the app. Users began noticing something weird going on with their phones: their default browsers kept getting hijacked and redirected to random advertisements, seemingly out of nowhere.

Generally, when this sort of thing happens it’s because the app was recently sold. That’s not the case here.

It is frightening that with one update an app can turn malicious while going under the radar of Google Play Protect. It is baffling to me that an app developer with a popular app would turn it into malware. Was this the scheme all along, to have an app lie dormant, waiting to strike after it reaches popularity? I guess we will never know.

Posted on February 16, 2021 at 6:13 AMView Comments

Deliberately Playing Copyrighted Music to Avoid Being Live-Streamed

Vice is reporting on a new police hack: playing copyrighted music when being filmed by citizens, trying to provoke social media sites into taking the videos down and maybe even banning the filmers:

In a separate part of the video, which Devermont says was filmed later that same afternoon, Devermont approaches [BHPD Sgt. Billy] Fair outside. The interaction plays out almost exactly like it did in the department—when Devermont starts asking questions, Fair turns on the music.

Devermont backs away, and asks him to stop playing music. Fair says “I can’t hear you”—again, despite holding a phone that is blasting tunes.

Later, Fair starts berating Devermont’s livestreaming account, saying “I read the comments [on your account], they talk about how fake you are.” He then holds out his phone, which is still on full blast, and walks toward Devermont, saying “Listen to the music”.

In a statement emailed to VICE News, Beverly Hills PD said that “the playing of music while accepting a complaint or answering questions is not a procedure that has been recommended by Beverly Hills Police command staff,” and that the videos of Fair were “currently under review.”

However, this is not the first time that a Beverly Hills police officer has done this, nor is Fair the only one.

In an archived clip from a livestream shared privately to VICE Media that Devermont has not publicly reposted but he says was taken weeks ago, another officer can be seen quickly swiping through his phone as Devermont approaches. By the time Devermont is close enough to speak to him, the officer’s phone is already blasting “In My Life” by the Beatles—a group whose rightsholders have notoriously sued Apple numerous times. If you want to get someone in trouble for copyright infringement, the Beatles are quite possibly your best bet.

As Devermont asks about the music, the officer points the phone at him, asking, “Do you like it?”

Clever, really, and an illustration of the problem with context-free copyright enforcement.

Posted on February 15, 2021 at 1:11 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.