Feeds

Turing test challenges spam filters

Fuzzy PDF menace

Remote control for virtualized desktops

Spammers have turned a widely-used anti-spam trick - fuzzy text that computers cannot recognise - to their own advantage, according to the head of an anti-spam software developer.

The distorted text images are arriving in PDF files touting German penny stocks, in yet another iteration of the pump-and-dump scam that's been around for a while now.

What's different from earlier image spam is not only that these are PDFs, which adds an extra layer of complexity to the task of filtering out spam, but the text inside is deliberately distorted to make it extra-hard for computers to recognise.

Neil Cook, European technology chief at anti-spam specialist Cloudmark, called it "a kind of Turing test for spam filters".

He added: "We've been seeing a lot of PDF stock spams for the last 10 days or so, and there was another spike last night. Images are particularly easy for humans to pick up, but particularly hard for computers.

"These ones are distorted too - it's the same technique that websites use to keep spammers off by making visitors type in distorted text during registration, and now the spammers are using it on us."

Cook claimed that Cloudmark's spam fingerprinting technology is holding off the unwanted PDFs for now, but said that new detection techniques could be needed if image spam continues to grow. ®

Intelligent flash storage arrays

More from The Register

next story
Webcam hacker pervs in MASS HOME INVASION
You thought you were all alone? Nope – change your password, says ICO
You really need to do some tech support for Aunty Agnes
Free anti-virus software, expires, stops updating and p0wns the world
Meet OneRNG: a fully-open entropy generator for a paranoid age
Kiwis to seek random investors for crowd-funded randomiser
USB coding anarchy: Consider all sticks licked
Thumb drive design ruled by almighty buck
Attack reveals 81 percent of Tor users but admins call for calm
Cisco Netflow a handy tool for cheapskate attackers
Privacy bods offer GOV SPY VICTIMS a FREE SPYWARE SNIFFER
Looks for gov malware that evades most antivirus
Patch NOW! Microsoft slings emergency bug fix at Windows admins
Vulnerability promotes lusers to domain overlords ... oops
prev story

Whitepapers

Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
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.
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.
Internet Security Threat Report 2014
An overview and analysis of the year in global threat activity: identify, analyze, and provide commentary on emerging trends in the dynamic threat landscape.
Intelligent flash storage arrays
Tegile Intelligent Storage Arrays with IntelliFlash helps IT boost storage utilization and effciency while delivering unmatched storage savings and performance.