Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Application Security //

Malware detection

12:35 PM
Larry Loeb
Larry Loeb
Larry Loeb

Over 500 Million Chrome iOS Sessions Hijacked in Massive Malvertising Campaign

Confiant has spotted the known threat actor eGobbler back in action.

Confiant has spotted the known threat actor eGobbler back in action. This group is well-known for attempting its campaigns around holidays, which is when it assumes there will be increased consumer traffic.

But this go-around the group is exploiting a currently unpatched flaw in the Chrome for iOS browser, to bypass sandboxing and hijack user sessions. This means that iPhone and iPad users are directly targeted.

eGobbler has historically used the ".world" TLD for their landing media like pop-ups, but this campaign seems to be using ".site" TLDs for web-based content.

eGobbler's main session hijacking mechanism in this case, however, was pop-up based. This is a change in strategy since when a browser's pop-up blocker is working it will stop the pop-up from appearing. Session hijacking happens when a user is redirected to another site or landing page. Alternatively, a pop-up can appear that one can't exit out of. The served pages look like ads from well-known brands, but they aren't. If clicked, a malicious payload is then deployed to the user.

Confiant has said that they "discovered techniques that took advantage of iOS Chrome's detection around user activated pop-up detection, resulting in the circumvention of pop-up blocking." Since Chrome remains unpatched at the time of this writing, Confiant is not revealing the exact code details of how this is done. That the exploit is able to bypass that need for user interaction should be impossible according to the same-origin policy (as it pertains to cross-origin iframes).

Additionally, this exploit also completely circumvents the browser's anti-redirect functionality. The attacker no longer needs to even spawn a redirect in order to hijack the user session. This latest hijacking lasted six days and started on Saturday, April 6. Confiant say that it was composed of eight individual campaigns and over 30 fake creatives. While the targeting was primarily US based, European publishers saw significant impact as well.

Confiant thinks over 500 million user sessions were exposed to the hijacking. They also said that "With half a billion user sessions impacted, this is among the top three massive malvertising campaigns that we have seen in the last 18 months."

eGobble will typically use cloaked intermediate CDN domains as part of their ad delivery. The domains may sit behind at least a single layer of client-side fingerprinting.

There remains a question about whether some of the hijacking tricks that are being used on Chrome can also be applied to Apple's Safari. Until explicit details of the exploit are known, no solid answer can be made.

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 9/25/2020
Hacking Yourself: Marie Moe and Pacemaker Security
Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
Startup Aims to Map and Track All the IT and Security Things
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
Register for Dark Reading Newsletters
White Papers
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...