Entries Tagged "Android"

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New Way to Covertly Track Android Users

Researchers have discovered a new way to covertly track Android users. Both Meta and Yandex were using it, but have suddenly stopped now that they have been caught.

The details are interesting, and worth reading in detail:

Tracking code that Meta and Russia-based Yandex embed into millions of websites is de-anonymizing visitors by abusing legitimate Internet protocols, causing Chrome and other browsers to surreptitiously send unique identifiers to native apps installed on a device, researchers have discovered. Google says it’s investigating the abuse, which allows Meta and Yandex to convert ephemeral web identifiers into persistent mobile app user identities.

The covert tracking—­implemented in the Meta Pixel and Yandex Metrica trackers­—allows Meta and Yandex to bypass core security and privacy protections provided by both the Android operating system and browsers that run on it. Android sandboxing, for instance, isolates processes to prevent them from interacting with the OS and any other app installed on the device, cutting off access to sensitive data or privileged system resources. Defenses such as state partitioning and storage partitioning, which are built into all major browsers, store site cookies and other data associated with a website in containers that are unique to every top-level website domain to ensure they’re off-limits for every other site.

Washington Post article.

Posted on June 9, 2025 at 6:54 AM • View Comments

PIN-Stealing Android Malware

This is an old piece of malware—the Chameleon Android banking Trojan—that now disables biometric authentication in order to steal the PIN:

The second notable new feature is the ability to interrupt biometric operations on the device, like fingerprint and face unlock, by using the Accessibility service to force a fallback to PIN or password authentication.

The malware captures any PINs and passwords the victim enters to unlock their device and can later use them to unlock the device at will to perform malicious activities hidden from view.

Posted on January 9, 2024 at 7:03 AM • View Comments

Leaked Signing Keys Are Being Used to Sign Malware

A bunch of Android OEM signing keys have been leaked or stolen, and they are actively being used to sign malware.

Łukasz Siewierski, a member of Google’s Android Security Team, has a post on the Android Partner Vulnerability Initiative (AVPI) issue tracker detailing leaked platform certificate keys that are actively being used to sign malware. The post is just a list of the keys, but running each one through APKMirror or Google’s VirusTotal site will put names to some of the compromised keys: Samsung, LG, and Mediatek are the heavy hitters on the list of leaked keys, along with some smaller OEMs like Revoview and Szroco, which makes Walmart’s Onn tablets.

This is a huge problem. The whole system of authentication rests on the assumption that signing keys are kept secret by the legitimate signers. Once that assumption is broken, all bets are off:

Samsung’s compromised key is used for everything: Samsung Pay, Bixby, Samsung Account, the phone app, and a million other things you can find on the 101 pages of results for that key. It would be possible to craft a malicious update for any one of these apps, and Android would be happy to install it overtop of the real app. Some of the updates are from today, indicating Samsung has still not changed the key.

Posted on December 8, 2022 at 7:08 AM • View Comments

Differences in App Security/Privacy Based on Country

Depending on where you are when you download your Android apps, it might collect more or less data about you.

The apps we downloaded from Google Play also showed differences based on country in their security and privacy capabilities. One hundred twenty-seven apps varied in what the apps were allowed to access on users’ mobile phones, 49 of which had additional permissions deemed “dangerous” by Google. Apps in Bahrain, Tunisia and Canada requested the most additional dangerous permissions.

Three VPN apps enable clear text communication in some countries, which allows unauthorized access to users’ communications. One hundred and eighteen apps varied in the number of ad trackers included in an app in some countries, with the categories Games, Entertainment and Social, with Iran and Ukraine having the most increases in the number of ad trackers compared to the baseline number common to all countries.

One hundred and three apps have differences based on country in their privacy policies. Users in countries not covered by data protection regulations, such as GDPR in the EU and the California Consumer Privacy Act in the U.S., are at higher privacy risk. For instance, 71 apps available from Google Play have clauses to comply with GDPR only in the EU and CCPA only in the U.S. Twenty-eight apps that use dangerous permissions make no mention of it, despite Google’s policy requiring them to do so.

Research paper: “A Large-scale Investigation into Geodifferences in Mobile Apps“:

Abstract: Recent studies on the web ecosystem have been raising alarms on the increasing geodifferences in access to Internet content and services due to Internet censorship and geoblocking. However, geodifferences in the mobile app ecosystem have received limited attention, even though apps are central to how mobile users communicate and consume Internet content. We present the first large-scale measurement study of geodifferences in the mobile app ecosystem. We design a semi-automatic, parallel measurement testbed that we use to collect 5,684 popular apps from Google Play in 26 countries. In all, we collected 117,233 apk files and 112,607 privacy policies for those apps. Our results show high amounts of geoblocking with 3,672 apps geoblocked in at least one of our countries. While our data corroborates anecdotal evidence of takedowns due to government requests, unlike common perception, we find that blocking by developers is significantly higher than takedowns in all our countries, and has the most influence on geoblocking in the mobile app ecosystem. We also find instances of developers releasing different app versions to different countries, some with weaker security settings or privacy disclosures that expose users to higher security and privacy risks. We provide recommendations for app market proprietors to address the issues discovered.

EDITED TO ADD (10/14): Project website.

Posted on September 29, 2022 at 6:14 AM • View Comments

Samsung Encryption Flaw

Researchers have found a major encryption flaw in 100 million Samsung Galaxy phones.

From the abstract:

In this work, we expose the cryptographic design and implementation of Android’s Hardware-Backed Keystore in Samsung’s Galaxy S8, S9, S10, S20, and S21 flagship devices. We reversed-engineered and provide a detailed description of the cryptographic design and code structure, and we unveil severe design flaws. We present an IV reuse attack on AES-GCM that allows an attacker to extract hardware-protected key material, and a downgrade attack that makes even the latest Samsung devices vulnerable to the IV reuse attack. We demonstrate working key extraction attacks on the latest devices. We also show the implications of our attacks on two higher-level cryptographic protocols between the TrustZone and a remote server: we demonstrate a working FIDO2 WebAuthn login bypass and a compromise of Google’s Secure Key Import.

Here are the details:

As we discussed in Section 3, the wrapping key used to encrypt the key blobs (HDK) is derived using a salt value computed by the Keymaster TA. In v15 and v20-s9 blobs, the salt is a deterministic function that depends only on the application ID and application data (and constant strings), which the Normal World client fully controls. This means that for a given application, all key blobs will be encrypted using the same key. As the blobs are encrypted in AES-GCM mode-of-operation, the security of the resulting encryption scheme depends on its IV values never being reused.

Gadzooks. That’s a really embarrassing mistake. GSM needs a new nonce for every encryption. Samsung took a secure cipher mode and implemented it insecurely.

News article.

Posted on March 4, 2022 at 6:19 AM • View Comments

System Update: New Android Malware

Researchers have discovered a new Android app called “System Update” that is a sophisticated Remote-Access Trojan (RAT). From a news article:

The broad range of data that this sneaky little bastard is capable of stealing is pretty horrifying. It includes: instant messenger messages and database files; call logs and phone contacts; Whatsapp messages and databases; pictures and videos; all of your text messages; and information on pretty much everything else that is on your phone (it will inventory the rest of the apps on your phone, for instance).

The app can also monitor your GPS location (so it knows exactly where you are), hijack your phone’s camera to take pictures, review your browser’s search history and bookmarks, and turn on the phone mic to record audio.

The app’s spying capabilities are triggered whenever the device receives new information. Researchers write that the RAT is constantly on the lookout for “any activity of interest, such as a phone call, to immediately record the conversation, collect the updated call log, and then upload the contents to the C&C server as an encrypted ZIP file.” After thieving your data, the app will subsequently erase evidence of its own activity, hiding what it has been doing.

This is a sophisticated piece of malware. It feels like the product of a national intelligence agency or—and I think more likely—one of the cyberweapons arms manufacturers that sells this kind of capability to governments around the world.

Posted on March 30, 2021 at 10:00 AM • View 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 AM • View Comments

NoxPlayer Android Emulator Supply-Chain Attack

It seems to be the season of sophisticated supply-chain attacks.

This one is in the NoxPlayer Android emulator:

ESET says that based on evidence its researchers gathered, a threat actor compromised one of the company’s official API (api.bignox.com) and file-hosting servers (res06.bignox.com).

Using this access, hackers tampered with the download URL of NoxPlayer updates in the API server to deliver malware to NoxPlayer users.

[…]

Despite evidence implying that attackers had access to BigNox servers since at least September 2020, ESET said the threat actor didn’t target all of the company’s users but instead focused on specific machines, suggesting this was a highly-targeted attack looking to infect only a certain class of users.

Until today, and based on its own telemetry, ESET said it spotted malware-laced NoxPlayer updates being delivered to only five victims, located in Taiwan, Hong Kong, and Sri Lanka.

I don’t know if there are actually more supply-chain attacks occurring right now. More likely is that they’ve been happening for a while, and we have recently become more diligent about looking for them.

Posted on February 8, 2021 at 6:34 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.