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.

Vulnerabilities / Threats

6/15/2016
08:00 AM
Connect Directly
Twitter
RSS
E-Mail
50%
50%

Windows 'BadTunnel' Attack Hijacks Network Traffic

Newly discovered -- and now patched -- Windows design flaw affects all versions of Windows.

A researcher in China has discovered a design flaw in Microsoft Windows that affects all versions of the operating system—including Windows 10—and lets an attacker hijack a victim organization’s network traffic.

Microsoft this week issued a patch for the so-called “BadTunnel” bug found by Yang Yu, director of Xuanwu Lab of Tencent in Beijing. Yu will detail and demonstrate his findings on the Windows flaw in August at Black Hat USA in Las Vegas in his presentation BadTunnel: How Do I Get Big Brother Power? 

“This vulnerability has a massive security impact – probably the widest impact in the history of Windows,” Yu said an an interview with Dark Reading conducted via email. “It not only can be exploited through many different channels, but also exists in all Windows versions released during the past 20 years. It can be exploited silently with a near perfect success rate.”

BadTunnel isn’t a typical coding-error flaw: it’s a combination of issues that together allow for an exploit. “This vulnerability is caused by a series of seemingly correct implementations, which includes a transport layer protocol, an application layer protocol, a few specific usage of application protocol by the operating system, and several protocol implementations used by firewalls and NAT devices,” Yu explains.

It can be exploited via all versions of Microsoft Office, Edge, Internet Explorer, and via several third-party apps on Windows, he says. Unlike most attacks, it doesn’t even require malware, although an attacker could deploy malware as well, he says. That makes it even more difficult to detect when a BadTunnel attack is under way, he notes. An attacker could also execute the attack via IIS and Apache Web servers, as well as via a thumb drive.

Yu says BadTunnel is basically a technique for NetBIOS-spoofing across networks: the attacker can get access to network traffic without being on the victim’s network, and also bypass firewall and Network Address Translation (NAT) devices.  

It basically works like this: the attacker gets a victim to visit a rigged web page via IE or Edge, or to open a rigged Office document (or install a malicious flash drive). The attacker’s site appears as either a file server or a local print server, and hijacks the victim’s network traffic – HTTP, Windows Updates, and even Certificated Revocation List updates via Microsoft’s CryptoAPI.

BadTunnel exploits a series of security weaknesses, including how Windows resolves network names and accepts responses; how  IE and Edge browsers support webpages with embedded content; how Windows handles network paths via an IP address; how NetBIOS Name Service NB and NBSTAT queries handle transactions; and how Windows handles queries on the same UDP port (137) -- all of which when lumped together make the network vulnerable to a BadTunnel attack.

Here’s an attack scenario, as explained in Yu’s technical paper:

1.  Alice and Bob can be located anywhere on their network, and have firewall and NAT devices in-between, as long as Bob’s 137/UDP port is reachable by Alice.

2.  Bob closes 139 and 445 port, but listens on 137/UDP port.

3.  Alice is convinced to access a file URI or UNC path that points to Bob, and another hostname based URI such as “http://WPAD/x.jpg” or “http://FileServer/x.jpg”. Alice will send a NBNS NBSTAT query to Bob, and also send a NBNS NB query to the LAN broadcast address.

4.  If Bob blocks access to 139 and 445 port using a firewall, Alice will send a NBNS NBSTAT query after approximately 22 seconds. If Bob instead closed 139 and 445 port by disabling Server Windows service or NetBIOS over TCP/IP protocol, Alice do not need to wait for connection to time out before send the query.

5.  When Bob received NBNS NBSTAT query sent by Alice, Bob forge a NBNS NB response by predicting the transaction id, and send to Alice. If a heartbeat packet is sent every few second, most firewall and NAT devices will keep the 137/UDP<->137/UDP tunnel open.

6.  Alice will now add the resolved address sent by Bob to the NBT cache. The default TTL for NBT cache entry is 600 seconds.

Bob then hijacks Alice’s network traffic by posing as a Web Proxy Auto-Discovery Protocol (WPAD) or Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) server. WPAD hijacking is nothing new, Yu notes: HD Moore & Valsmith presented research on this in 2007 at Black Hat USA, and the Flame worm employed a similar attack method.

Black Hat USA returns to the fabulous Mandalay Bay in Las Vegas, Nevada July 30 through Aug. 4, 2016. Click for information on the conference schedule and to register.

 

Yu says his discovery of BadTunnel began during a flight last year. “One day last year, when I was on an airplane, I got bored. I started to imagine different security problems and suddenly came up with a brand new attack scenario,” he recalls. “After the trip, I immediately started testing on different system configurations, and finally discovered this vulnerability in the Windows operating system.”

Yu first reported his finding to Microsoft in January, he says. He says he’s not aware of any attacks in the wild.

His advice to Windows users: “For the average user, always make sure you have the latest available patches. If for some reason you can not install the patch, I suggest you disable the NetBIOS over TCP/IP to prevent BadTunnel attack,” he says.

Related Content:

 

 

Kelly Jackson Higgins is the Executive Editor of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise ... View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Frankie89
50%
50%
Frankie89,
User Rank: Apprentice
5/9/2017 | 5:18:59 PM
The security of homepages
really great post but at the and the weak spot is always the bad informed user
Edge-DRsplash-10-edge-articles
7 Old IT Things Every New InfoSec Pro Should Know
Joan Goodchild, Staff Editor,  4/20/2021
News
Cloud-Native Businesses Struggle With Security
Robert Lemos, Contributing Writer,  5/6/2021
Commentary
Defending Against Web Scraping Attacks
Rob Simon, Principal Security Consultant at TrustedSec,  5/7/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
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-2021-29040
PUBLISHED: 2021-05-16
The JSON web services in Liferay Portal 7.3.4 and earlier, and Liferay DXP 7.0 before fix pack 97, 7.1 before fix pack 20 and 7.2 before fix pack 10 may provide overly verbose error messages, which allows remote attackers to use the contents of error messages to help launch another, more focused att...
CVE-2021-29041
PUBLISHED: 2021-05-16
Denial-of-service (DoS) vulnerability in the Multi-Factor Authentication module in Liferay DXP 7.3 before fix pack 1 allows remote authenticated attackers to prevent any user from authenticating by (1) enabling Time-based One-time password (TOTP) on behalf of the other user or (2) modifying the othe...
CVE-2021-29047
PUBLISHED: 2021-05-16
The SimpleCaptcha implementation in Liferay Portal 7.3.4, 7.3.5 and Liferay DXP 7.3 before fix pack 1 does not invalidate CAPTCHA answers after it is used, which allows remote attackers to repeatedly perform actions protected by a CAPTCHA challenge by reusing the same CAPTCHA answer.
CVE-2021-22668
PUBLISHED: 2021-05-16
Delta Industrial Automation CNCSoft ScreenEditor Versions 1.01.28 (with ScreenEditor Version 1.01.2) and prior are vulnerable to an out-of-bounds read while processing project files, which may allow an attacker to execute arbitrary code.
CVE-2021-29039
PUBLISHED: 2021-05-16
Cross-site scripting (XSS) vulnerability in the Asset module's categories administration page in Liferay Portal 7.3.4 allows remote attackers to inject arbitrary web script or HTML via the site name.