Feeds

Researchers release point-and-click website exploitation tool

'Tons' of vulnerable sites

Choosing a cloud hosting partner with confidence

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. ®

Internet Security Threat Report 2014

More from The Register

next story
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?
Russian hackers exploit 'Sandworm' bug 'to spy on NATO, EU PCs'
Fix imminent from Microsoft for Vista, Server 2008, other stuff
Edward who? GCHQ boss dodges Snowden topic during last speech
UK spies would rather 'walk' than do 'mass surveillance'
Microsoft pulls another dodgy patch
Redmond makes a hash of hashing add-on
'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
China is ALREADY spying on Apple iCloud users, claims watchdog
Attack harvests users' info at iPhone 6 launch
Carders punch holes through Staples
Investigation launched into East Coast stores
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.
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.
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.