Android Ad-Fraud Scheme

BuzzFeed is reporting on a scheme where fraudsters buy legitimate Android apps, track users’ behavior in order to mimic it in a way that evades bot detectors, and then uses bots to perpetuate an ad-fraud scheme. After being provided with a list of the apps and websites connected to the scheme, Google investigated and found that dozens of the apps…

BuzzFeed is reporting on a scheme where fraudsters buy legitimate Android apps, track users' behavior in order to mimic it in a way that evades bot detectors, and then uses bots to perpetuate an ad-fraud scheme.

After being provided with a list of the apps and websites connected to the scheme, Google investigated and found that dozens of the apps used its mobile advertising network. Its independent analysis confirmed the presence of a botnet driving traffic to websites and apps in the scheme. Google has removed more than 30 apps from the Play store, and terminated multiple publisher accounts with its ad networks. Google said that prior to being contacted by BuzzFeed News it had previously removed 10 apps in the scheme and blocked many of the websites. It continues to investigate, and published a blog post to detail its findings.

The company estimates this operation stole close to $10 million from advertisers who used Google's ad network to place ads in the affected websites and apps. It said the vast majority of ads being placed in these apps and websites came via other major ad networks.

Lots of details in both the BuzzFeed and the Google links.

The Internet advertising industry is rife with fraud, at all levels. This is just one scheme among many.

from https://www.schneier.com/blog/

Facebook Is Using Your Two-Factor Authentication Phone Number to Target Advertising

From Kashmir Hill: Facebook is not content to use the contact information you willingly put into your Facebook profile for advertising. It is also using contact information you handed over for security purposes and contact information you didn’t hand over at all, but that was collected from other people’s contact books, a hidden layer of details Facebook has about you…

From Kashmir Hill:

Facebook is not content to use the contact information you willingly put into your Facebook profile for advertising. It is also using contact information you handed over for security purposes and contact information you didn't hand over at all, but that was collected from other people's contact books, a hidden layer of details Facebook has about you that I've come to call "shadow contact information." I managed to place an ad in front of Alan Mislove by targeting his shadow profile. This means that the junk email address that you hand over for discounts or for shady online shopping is likely associated with your account and being used to target you with ads.

Here's the research paper. Hill again:

They found that when a user gives Facebook a phone number for two-factor authentication or in order to receive alerts about new log-ins to a user's account, that phone number became targetable by an advertiser within a couple of weeks. So users who want their accounts to be more secure are forced to make a privacy trade-off and allow advertisers to more easily find them on the social network.

from https://www.schneier.com/blog/

Detecting Adblocker Blockers

Interesting research on the prevalence of adblock blockers: "Measuring and Disrupting Anti-Adblockers Using Differential Execution Analysis": Abstract: Millions of people use adblockers to remove intrusive and malicious ads as well as protect themselves against tracking and pervasive surveillance. Online publishers consider adblockers a major threat to the ad-powered "free" Web. They have started to retaliate against adblockers by employing anti-adblockers…

Interesting research on the prevalence of adblock blockers: "Measuring and Disrupting Anti-Adblockers Using Differential Execution Analysis":

Abstract: Millions of people use adblockers to remove intrusive and malicious ads as well as protect themselves against tracking and pervasive surveillance. Online publishers consider adblockers a major threat to the ad-powered "free" Web. They have started to retaliate against adblockers by employing anti-adblockers which can detect and stop adblock users. To counter this retaliation, adblockers in turn try to detect and filter anti-adblocking scripts. This back and forth has prompted an escalating arms race between adblockers and anti-adblockers.

We want to develop a comprehensive understanding of anti-adblockers, with the ultimate aim of enabling adblockers to bypass state-of-the-art anti-adblockers. In this paper, we present a differential execution analysis to automatically detect and analyze anti-adblockers. At a high level, we collect execution traces by visiting a website with and without adblockers. Through differential execution analysis, we are able to pinpoint the conditions that lead to the differences caused by anti-adblocking code. Using our system, we detect anti-adblockers on 30.5% of the Alexa top-10K websites which is 5-52 times more than reported in prior literature. Unlike prior work which is limited to detecting visible reactions (e.g., warning messages) by anti-adblockers, our system can discover attempts to detect adblockers even when there is no visible reaction. From manually checking one third of the detected websites, we find that the websites that have no visible reactions constitute over 90% of the cases, completely dominating the ones that have visible warning messages. Finally, based on our findings, we further develop JavaScript rewriting and API hooking based solutions (the latter implemented as a Chrome extension) to help adblockers bypass state-of-the-art anti-adblockers.

News article.

from https://www.schneier.com/blog/

Using Ultrasonic Beacons to Track Users

I’ve previously written about ad networks using ultrasonic communications to jump from one device to another. The idea is for devices like televisions to play ultrasonic codes in advertisements and for nearby smartphones to detect them. This way the two devices can be linked. Creepy, yes. And also increasingly common, as this research demonstrates: Privacy Threats through Ultrasonic Side Channels…

I've previously written about ad networks using ultrasonic communications to jump from one device to another. The idea is for devices like televisions to play ultrasonic codes in advertisements and for nearby smartphones to detect them. This way the two devices can be linked.

Creepy, yes. And also increasingly common, as this research demonstrates:

Privacy Threats through Ultrasonic Side Channels on Mobile Devices

by Daniel Arp, Erwin Quiring, Christian Wressnegger and Konrad Rieck

Abstract: Device tracking is a serious threat to the privacy of users, as it enables spying on their habits and activities. A recent practice embeds ultrasonic beacons in audio and tracks them using the microphone of mobile devices. This side channel allows an adversary to identify a user's current location, spy on her TV viewing habits or link together her different mobile devices. In this paper, we explore the capabilities, the current prevalence and technical limitations of this new tracking technique based on three commercial tracking solutions. To this end, we develop detection approaches for ultrasonic beacons and Android applications capable of processing these. Our findings confirm our privacy concerns: We spot ultrasonic beacons in various web media content and detect signals in 4 of 35 stores in two European cities that are used for location tracking. While we do not find ultrasonic beacons in TV streams from 7 countries, we spot 234 Android applications that are constantly listening for ultrasonic beacons in the background without the user's knowledge.

News article. BoingBoing post.

from https://www.schneier.com/blog/

Advances in Ad Blocking

Ad blockers represent the largest consumer boycott in human history. They’re also an arms race between the blockers and the blocker blockers. This article discusses a new ad-blocking technology that represents another advance in this arms race. I don’t think it will "put an end to the ad-blocking arms race," as the title proclaims, but it will definitely give the…

Ad blockers represent the largest consumer boycott in human history. They're also an arms race between the blockers and the blocker blockers. This article discusses a new ad-blocking technology that represents another advance in this arms race. I don't think it will "put an end to the ad-blocking arms race," as the title proclaims, but it will definitely give the blockers the upper hand.

The software, devised by Arvind Narayanan, Dillon Reisman, Jonathan Mayer, and Grant Storey, is novel in two major ways: First, it looks at the struggle between advertising and ad blockers as fundamentally a security problem that can be fought in much the same way antivirus programs attempt to block malware, using techniques borrowed from rootkits and built-in web browser customizability to stealthily block ads without being detected. Second, the team notes that there are regulations and laws on the books that give a fundamental advantage to consumers that cannot be easily changed, opening the door to a long-term ad-blocking solution.

Now if we could only block the data collection as well.

from https://www.schneier.com/blog/

WWW Malware Hides in Images

There’s new malware toolkit that uses steganography to hide in images: For the past two months, a new exploit kit has been serving malicious code hidden in the pixels of banner ads via a malvertising campaign that has been active on several high profile websites. Discovered by security researchers from ESET, this new exploit kit is named Stegano, from the…

There’s new malware toolkit that uses steganography to hide in images:

For the past two months, a new exploit kit has been serving malicious code hidden in the pixels of banner ads via a malvertising campaign that has been active on several high profile websites.

Discovered by security researchers from ESET, this new exploit kit is named Stegano, from the word steganography, which is a technique of hiding content inside other files.

In this particular scenario, malvertising campaign operators hid malicious code inside PNG images used for banner ads.

The crooks took a PNG image and altered the transparency value of several pixels. They then packed the modified image as an ad, for which they bought ad displays on several high-profile websites.

Since a large number of advertising networks allow advertisers to deliver JavaScript code with their ads, the crooks also included JS code that would parse the image, extract the pixel transparency values, and using a mathematical formula, convert those values into a character.

Slashdot thread.

Ultrasonic Hacking

Ad networks are surreptitiously using ultrasonic communications to jump from device to device. It should come as no surprise that this communications channel can be used to hack devices as well….

Ad networks are surreptitiously using ultrasonic communications to jump from device to device. It should come as no surprise that this communications channel can be used to hack devices as well.

from https://www.schneier.com/blog/