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

11/5/2009
01:36 PM
Connect Directly
Google+
Twitter
RSS
E-Mail
50%
50%

Little-Known Hole Lets Attacker Hit Main Website Domain Via Its Subdomains

Proof-of-concept demonstrates how exploits on Google, Expedia, Chase Manhattan subdomains could lead to compromises of their main sites

Turns out an exploit on a Website's subdomain can be used to attack the main domain: A researcher has released a proof-of-concept showing how cookies can be abused to execute such an insidious attack.

Michael Bailey, senior researcher for Foreground Security, published a paper this week that demonstrates how an exploit in a subdomain, such as mail.google.com, could be used to hack the main production domain, google.com, all because of the way browsers handle cookies.

"There's no specific vulnerability here, but it's widening the attack surface for any large organization that has more than one [Web] server set up. A [vulnerability] in any one of those servers can affect all the rest," Bailey says.

Most Web developers aren't aware that a vulnerability in a subdomain could be used to target the main domain. "We're trying to get the message out that now you have to treat everything [in the domain] as though someone can compromise your crown jewels," says Michael Murray, CSO for Foreground. "You have to realize that every vulnerability, every attack vector in those subdomains, can be used to compromise [other areas of the domain]," he says.

It all boils down to the browsers themselves. Within the DNS architecture, the main domain -- fortune500company.com, for instance -- has control over its subdomains, such as development.fortune500company.com. Development.fortune500company.com has no authority to change anything on the main fortune500company.com site.

But browsers do the reverse, Murray says. Development.fortune500company.com can set cookies for fortune500company.com, the main domain. That leaves the door open for cookie-tampering, he says, when the subdomain has an exploitable vulnerability, such as cross-site scripting (XSS) or cross-site request forgery (CSRF).

"Most developers don't care if there's an XSS bug in the development site. But now all of those vulnerabilities are as important as an XSS in the main site," Murray says.

There's no actual patch to protect against the attack -- it's more about how Web developers set up their site domains. And when the site uses third-party content, it's even more at risk, according to the researchers.

In his paper (PDF), Foreground's Bailey showed PoCs with Google, Expedia, and Chase Manhattan's Websites. "The Chase online banking app could be compromised from one of the marketing companies they partnered with," Bailey says. His example in the PoC showed how images.chase.com, images.capitalone.com, and online.chasevisasignature.com all point to content from images.bigfootinteractive.com, an advertising agency's server. That server is actually vulnerable to XSS, he found, so it can be used to compromise a legitimate Chase user's banking session.

The answer, he says, is to use a completely different subdomain from your main one when pointing to content from a third party.

Bailey says so far he hasn't seen any actual attacks exploiting this. "But I have seen mentions of similar research on black hat forums. I know this isn't completely new to black hats," he says. He recommends users clean up their cookies regularly and use separate Web browsers or browser sessions for sensitive browsing activities.

Meanwhile, any flaw on a subdomain is putting all users on the main domain at risk. "They've got to treat a development site the same as the online banking site," Foreground's Murray says. "The implications are huge here."

Have a comment on this story? Please click "Discuss" below. If you'd like to contact Dark Reading's editors directly, send us a message. 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

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
Sodinokibi Ransomware: Where Attackers' Money Goes
Kelly Sheridan, Staff Editor, Dark Reading,  10/15/2019
Data Privacy Protections for the Most Vulnerable -- Children
Dimitri Sirota, Founder & CEO of BigID,  10/17/2019
7 SMB Security Tips That Will Keep Your Company Safe
Steve Zurier, Contributing Writer,  10/11/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: The old using of sock puppets for Shoulder Surfing technique. 
Current Issue
7 Threats & Disruptive Forces Changing the Face of Cybersecurity
This Dark Reading Tech Digest gives an in-depth look at the biggest emerging threats and disruptive forces that are changing the face of cybersecurity today.
Flash Poll
2019 Online Malware and Threats
2019 Online Malware and Threats
As cyberattacks become more frequent and more sophisticated, enterprise security teams are under unprecedented pressure to respond. Is your organization ready?
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-8216
PUBLISHED: 2019-10-17
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure .
CVE-2019-8217
PUBLISHED: 2019-10-17
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an use after free vulnerability. Successful exploitation could lead to arbitrary code execution .
CVE-2019-8218
PUBLISHED: 2019-10-17
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an out-of-bounds read vulnerability. Successful exploitation could lead to information disclosure .
CVE-2019-8219
PUBLISHED: 2019-10-17
Adobe Acrobat and Reader versions , 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an use after free vulnerability. Successful exploitation could lead to arbitrary code execution .
CVE-2019-8220
PUBLISHED: 2019-10-17
Adobe Acrobat and Reader versions, 2019.012.20040 and earlier, 2017.011.30148 and earlier, 2017.011.30148 and earlier, 2015.006.30503 and earlier, and 2015.006.30503 and earlier have an use after free vulnerability. Successful exploitation could lead to arbitrary code execution .