Feeds

Serious web vuln found in 8 million Flash files

XSS R Us

Choosing a cloud hosting partner with confidence

A security researcher has identified more than 8 million Adobe Flash files that make the websites hosting them vulnerable to attacks that target visitors with malicious code.

The Flash files are contained on a wide variety of sites operated by online casinos, news organizations, banks, and professional sports teams. They make the pages where they reside susceptible to XSS, or cross-site scripting, attacks that have the potential to inject malicious code and content into a visitor's browser and in some cases steal credentials used to authenticate user accounts.

The researcher, who goes by the moniker MustLive, said the Flash files contain poorly written ActionScript used to count the number of times a banner has been clicked and typically contain the clickTAG or url parameters. Google searches here and here identified a total more than 8.3 million of them on sites hosted by the New York Giants football team, Praguepost.com and ParadaisPoker.com. Because Google results are often abbreviated, the actual number is probably higher.

MustLive said websites that host the buggy content aren't automatically vulnerable to XSS exploits. Indeed, even though the pages on the official Citibank website included such content, XSS attacks that tried to exploit them failed.

But the researcher provided a wealth of examples of websites that were made vulnerable by the Adobe files, which provide graphics that move and are often referred to as SWFs, because of the three-letter suffix their file names carry.

Examples of pages vulnerable to malicious code injection are here, here and here. MustLive said this page can be exploited to reveal user cookies when accessed by virtually any browser.

Using the above Google searchers, El Reg was able to identify its own working exploits, including this one on the official website for the New York Giants. (In many cases, the scripts launch only after the user has clicked an object on the page).

It's by no means the first time someone has identified a sprawling body of SWF files that threaten the security of the sites hosting them. Two years ago, researchers documented serious vulnerabilities in Adobe-based content that exposed more than 10,000 sites to attack.

The threat was particularly difficult to eradicate because webmasters had to patch their content-generation software and then render the animation scripts all over again. Months after the problem was identified, many websites still hadn't bothered to take action.

Last year, MustLive reported 215,000 vulnerable Flash files, a number he later raised to the millions. That content was also made vulnerable by buggy ActionScript.

It should be said that the vulnerabilities exposed in the latest discovery are the result of bugs introduced by sloppy rendering, rather than vulnerable Adobe software. Adobe provides security guidance here for designing banners with tracking capabilities. MustLive provides additional advice at the end of his blog post documenting the vulnerable SWF files. ®

Beginner's guide to SSL certificates

More from The Register

next story
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
FYI: OS X Yosemite's Spotlight tells Apple EVERYTHING you're looking for
It's on by default – didn't you read the small print?
'LulzSec leader Aush0k' found to be naughty boy not worthy of jail
15 months home detention leaves egg on feds' faces as they grab for more power
Forget passwords, let's use SELFIES, says Obama's cyber tsar
Michael Daniel wants to kill passwords dead
Kill off SSL 3.0 NOW: HTTPS savaged by vicious POODLE
Pull it out ASAP, it is SWISS CHEESE
Facebook slurps 'paste sites' for STOLEN passwords, sprinkles on hash and salt
Zuck's ad empire DOESN'T see details in plain text. Phew!
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.