Feeds

Researchers release point-and-click website exploitation tool

'Tons' of vulnerable sites

The Essential Guide to IT Transformation

Researchers have released software that exposes private information and executes arbitrary code on sensitive websites by exploiting weaknesses in a widely used web development technology.

Short for Padding Oracle Exploitation Tool, Poet is able to decrypt secret data encrypted by the JavaServer Faces web development framework without knowing the secret key. Attackers can use the technique to access private customer data on websites operated by banks, e-commerce companies and other businesses, according to a paper (PDF) released in February by researchers Juliano Rizzo and Thai Duong. In some cases, the exploit can be used to run malicious software on the underlying server.

Released Monday, Poet exploits a well-known vulnerability in the way many websites encrypt text stored in cookies, hidden HTML fields and request parameters. The text is designed to help servers keep track of purchases, user preferences and other settings while at the same time ensuring account credentials and other sensitive data can't be intercepted. By modifying the encrypted information and sending it back to the server, the attackers can recover the plaintext for small chunks of the data, allowing them to access passwords and restricted parts of a webserver.

The fatal flaw making exploitation possible is the failure of JavaServer Faces to implement AES/DES encryption algorithms correctly. The scheme provides no way to sign the ciphertext or authenticate the block cipher mode.

“The tool exploits a very common mistake -- using encryption alone instead of encryption + authentication/integrity protection," Rizzo told The Register. "You can get information about the plaintext from the server reaction.”

The attack can be used by crawling a target website for strings of encrypted strings and then modifying the last block of the ciphertext by a random value and sending it back to the server. The resulting error messages are then used to decipher the text, allowing attackers to bypass CAPTCHAs, view customer account numbers and even create webpages that will execute malicious software on the underlying server. Attackers can also use the technique to map all ciphertexts to corresponding plaintexts, a feat that breaks a website's underlying cryptosystem.

Attackers can also use Google to find websites that are vulnerable to attack. Queries such as “Given final block not properly padded” and “javax.crypto.BadPaddingException” reveal “tons” of exposed web applications, the researchers said.

The researchers tested the attack in JavaServer Faces implemented into the Apache webserver, as well as Sun's Mojarra. They said many other implementations are also likely to be vulnerable.

Poet runs on Windows, Mac OS X and Linux and is available here . Video showing the exploit code in action is here. ®

Build a business case: developing custom apps

More from The Register

next story
14 antivirus apps found to have security problems
Vendors just don't care, says researcher, after finding basic boo-boos in security software
'Things' on the Internet-of-things have 25 vulnerabilities apiece
Leaking sprinklers, overheated thermostats and picked locks all online
iWallet: No BONKING PLEASE, we're Apple
BLE-ding iPhones, not NFC bonkers, will drive trend - marketeers
Only '3% of web servers in top corps' fully fixed after Heartbleed snafu
Just slapping a patched OpenSSL on a machine ain't going to cut it, we're told
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Secure microkernel that uses maths to be 'bug free' goes open source
Hacker-repelling, drone-protecting code will soon be yours to tweak as you see fit
Israel's Iron Dome missile tech stolen by Chinese hackers
Corporate raiders Comment Crew fingered for attacks
Tor attack nodes RIPPED MASKS off users for 6 MONTHS
Traffic confirmation attack bared users' privates - but to whom?
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
prev story

Whitepapers

Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.