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.

IoT
End of Bibblio RCM includes -->

FragAttacks Foil 2 Decades of Wireless Security

Wireless security protocols have improved, but product vendors continue to make implementation errors that allow a variety of attacks.

The evolution of wireless security could at best be described as trial and error. The initial standard that debuted in the late 1990s — Wired Equivalent Privacy (WEP) — had significant security problems, and the first two version of Wireless Protected Access, WPA and WPA2, both have been found to be vulnerable to a variety of other security issues.

The trials continue with a host of so-called fragmentation attacks, or FragAttacks, that abuse the aggregation and fragmentation to allow machine-in-the-middle attacks. Details of the vulnerabilities, which have been kept secret for nine months, were disclosed at the Black Hat USA briefings on Aug. 5.

The issues occur in the way that small network packets are combined for transport, known as aggregation, or the way that large network packets are split up to improve reliability, known as aggregation. Even devices using WPA3, the latest wireless security standard, can be vulnerable, Mathy Vanhoef, a postdoctoral researcher at New York University Abu Dhabi, said during his Black Hat presentation.

"The fragmentation and aggregation functionality of Wi-Fi were never considered security-essential, so no one really looked at them," he said, adding: "This really shows that all implementations are vulnerable — even, surprisingly, those that don't support fragmentation and those that don't support aggregation."

The vulnerabilities — which Vanhoef described as design flaws in the IEEE 802.11 standard, more commonly known as Wi-Fi — were described in a paper released in June. The issues allow a local attacker who has fooled a victim into connecting to an attacker-controlled server to then insert themselves into the Wi-Fi network as a machine in the middle.

Vanhoef characterized these as design flaws because the specific mitigations are optional and not required, a lesson for future implementers of the standard.

"We should adopt defenses early, even if the concerns are theoretic, because that, for example, would have prevented the aggregation design flaw," he said. In addition, testing the software should be part of the credentialing process for vendors' devices, he added. "We should keep fuzzing devices; ... the Wi-Fi Alliance could fuzz devices while they are being certified."

Vanhoef discovered three design flaws in the current Wi-Fi standard. The first, CVE-2020-24588, allows an attacker to abuse the way that Wi-Fi aggregates smaller data packets into larger frames to optimize wireless data rates. The researcher used the attack to send victims on the local Wi-Fi network to an attacker-controlled domain name service (DNS) server, and then onto malicious website.

A second flaw, CVE-2020-24587, takes advantage of the specification's failure to verify that each fragment of a packet is using the same encryption key. Using a specially constructed packet, an attacker can append code onto a legitimate fragment of the victim's original packet.

"While this actually seems secure, the problems begin when fragmentation is combined with session-key renewal," Vanhoef said. "When the key is renewed, the packet numbers will be reset to 0. ... The problem is that the receiver will reassemble the packets even if the sender used different encryption keys."

The final flaw, CVE-2020-24586, takes advantage of the lack of deletion of packet fragments from legitimate users on a Wi-Fi network. A malicious user can cache packets on the Wi-Fi network, which, under certain circumstances, will be inserted into other users' packets.

To allow vendors and researchers to verify the issues, Vanhoef published a testing tool to GitHub. The software requires the credentials of the Wi-Fi network, so it is not considered an attack tool.

Many device makers still do not handle vulnerability disclosure well. Vanhoef worked with the Wi-Fi Alliance to disclose the issues to vendors, and most issued patches. Vanhoef modified the test tool for specific vendors and continues to work with the group to support vendors.

"To my surprise, some companies were not happy, even if they managed to write patches for most devices," he said. "I was actually happy that most devices got patches, because usually that is not the case for Wi-Fi."

At the end of 2020, two new security measures became standard for WPA3 — operating channel validation and beacon protection — and while they make the fragmentation attacks harder, they are still possible.

Veteran technology journalist of more than 20 years. Former research engineer. Written for more than two dozen publications, including CNET News.com, Dark Reading, MIT's Technology Review, Popular Science, and Wired News. Five awards for journalism, including Best Deadline ... View Full Bio

Comment  | 
Print  | 
More Insights
//Comments
Newest First  |  Oldest First  |  Threaded View
Edge-DRsplash-10-edge-articles
I Smell a RAT! New Cybersecurity Threats for the Crypto Industry
David Trepp, Partner, IT Assurance with accounting and advisory firm BPM LLP,  7/9/2021
News
Attacks on Kaseya Servers Led to Ransomware in Less Than 2 Hours
Robert Lemos, Contributing Writer,  7/7/2021
Commentary
It's in the Game (but It Shouldn't Be)
Tal Memran, Cybersecurity Expert, CYE,  7/9/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Creating an Effective Incident Response Plan
Security teams are realizing their organizations will experience a cyber incident at some point. An effective incident response plan that takes into account their specific requirements and has been tested is critical. This issue of Tech Insights also includes: -a look at the newly signed cyber-incident law, -how organizations can apply behavioral psychology to incident response, -and an overview of the Open Cybersecurity Schema Framework.
Flash Poll
How Enterprises are Developing Secure Applications
How Enterprises are Developing Secure Applications
Recent breaches of third-party apps are driving many organizations to think harder about the security of their off-the-shelf software as they continue to move left in secure software development practices.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2022-4194
PUBLISHED: 2022-11-30
Use after free in Accessibility in Google Chrome prior to 108.0.5359.71 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: Medium)
CVE-2022-4195
PUBLISHED: 2022-11-30
Insufficient policy enforcement in Safe Browsing in Google Chrome prior to 108.0.5359.71 allowed a remote attacker to bypass Safe Browsing warnings via a malicious file. (Chromium security severity: Medium)
CVE-2022-4175
PUBLISHED: 2022-11-30
Use after free in Camera Capture in Google Chrome prior to 108.0.5359.71 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page. (Chromium security severity: High)
CVE-2022-4176
PUBLISHED: 2022-11-30
Out of bounds write in Lacros Graphics in Google Chrome on Chrome OS and Lacros prior to 108.0.5359.71 allowed a remote attacker who convinced a user to engage in specific UI interactions to potentially exploit heap corruption via UI interactions. (Chromium security severity: High)
CVE-2022-4177
PUBLISHED: 2022-11-30
Use after free in Extensions in Google Chrome prior to 108.0.5359.71 allowed an attacker who convinced a user to install an extension to potentially exploit heap corruption via a crafted Chrome Extension and UI interaction. (Chromium security severity: High)