SafeUM
Home Blog Services Download Help About Recharge

Axarhöfði 14, 110 Reykjavik, Iceland

Iceland - 2015
SafeUM
Blog
Services
Download
Help
About
Recharge
Menu
Archive
TOP Security!
1 Oct 2015

Mobile ad network abused in DDoS attack

One of CloudFlare’s customers was recently hit by a distributed denial-of-service (DDoS) attack that appeared to leverage a mobile ad network and malicious JavaScript.

JavaScript-based DDoS attacks have been classified as Layer 7 attacks because they rely on apparently legitimate HTTP requests. Experts have been warning about the possibility of such attacks since 2010, but they’ve recently become a reality and are becoming increasingly problematic.

In April, researchers revealed the existence of a new tool used by the Chinese government for censorship enforcement. The tool, dubbed “Great Cannon,” relies on malicious JavaScript injected into unencrypted traffic in order to launch DDoS attacks against targeted websites. A different DDoS attack leveraging JavaScript was reported last week when an Imgur vulnerability was exploited to disrupt the imageboard 8chan. CloudFlare recently noticed a large number of HTTP requests aimed at one of its customers. The attack peaked at over 1 billion requests per hour, with a total of 4.5 billion requests reaching the content delivery network’s servers on the day of the attack.

The requests came from 650,000 unique IP addresses, 99.8 percent of them being traced to China. An analysis of the “User Agent” revealed that 80 percent of the requests came from mobile devices, in many cases from mobile apps and browsers that are popular in China. Researchers discovered that the websites from the “Referer” header pointed to an ad aggregator or a link farm. Malicious JavaScript hosted on these pages was designed to flood CloudFlare’s customer with XMLHttpRequest (XHR) requests.

While it’s difficult to precisely determine how such a large number of mobile devices ended up visiting the attack page, experts believe the most likely distribution vector is a mobile ad network. CloudFlare says it’s confident that the DDoS attack had not involved injection of TCP packets such as in the case of the Great Cannon.

Researchers believe that users casually surfing the Web from mobile devices were served an iframe containing an advertisement. The content was requested from an advertising network that served the attackers’ ads via the real-time bidding model. At this point, the malicious actors either served the attack page directly or they forwarded victims to it. Finally, the malicious JavaScript on the page was executed and it launched a flood of XHR requests towards CloudFlare’s servers.

In June, F5 Networks’ David Holmes explained why mobile DDoS never materialized. One of the main reasons, according to the security expert, is that mobile users mostly rely on dedicated apps to connect to various online services instead of using web browser as they do on desktop computers. This makes it less likely for a mobile device to be affected by a malvertising campaign.

However, the attack described by CloudFlare seems to show that mobile users can be just as exposed to ad infections. “Attacks like this form a new trend,” CloudFlare said in a blog post. “They present a great danger in the internet — defending against this type of flood is not easy for small website operators.”

Tags:
DDoS information leaks
Source:
SecurityWeek
1990
Other NEWS
3 Jul 2020 safeum news imgage An encrypted messaging service has been infiltrated by police
4 May 2020 safeum news imgage Two-Factor Authentication ​What Is It and Why You Should Use It
12 Dec 2019 safeum news imgage Encryption is under threat - this is how it affects you
4 Nov 2019 safeum news imgage Should Big Decisions Be Based on Data or Your Intuition?
7 Jun 2018 safeum news imgage VPNFilter malware infecting 500,000 devices is worse than we thought
4 Jun 2018 safeum news imgage Hackers target Booking.com in criminal bid to steal hundreds of thousands from customers
1 Jun 2018 safeum news imgage Operator of World's Top Internet Hub Sues German Spy Agency
30 May 2018 safeum news imgage US says North Korea behind malware attacks
29 May 2018 safeum news imgage Facebook and Google targeted as first GDPR complaints filed
25 May 2018 safeum news imgage A new reason to not buy these cheap Android devices
24 May 2018 safeum news imgage Flaws in smart pet devices, apps could come back to bite owners
23 May 2018 safeum news imgage Google sued for 'clandestine tracking' of 4.4m UK iPhone users' browsing data
21 May 2018 safeum news imgage LocationSmart reportedly leaked phone location data onto the web
18 May 2018 safeum news imgage The SEC created its own scammy ICO to teach investors a lesson
17 May 2018 safeum news imgage Thieves suck millions out of Mexican banks in transfer heist
All news
SafeUM
Confidential Terms of Use Our technologies Company
Follow us
Download
SafeUM © Safe Universal Messenger

Axarhöfði 14,
110 Reykjavik, Iceland

Iceland - 2015