Feeds

Using Android 4.3? Don't let malware snatch your private login keys

Bad news: One in ten devices suffer KeyStore flaw. Good news: It's hard to exploit

Intelligent flash storage arrays

If you're one of the 10.3 per cent of Android users running version 4.3, aka Jelly Bean, your login keys are at risk of theft – thanks to a vulnerability in the operating system's KeyStore software.

KeyStore, as the name suggests, stores a user's cryptographic keys, which are used by apps to log into services without the user having to retype their password.

But IBM researchers have found that the program is vulnerable to a classic stack-based buffer overflow by an attacker who is able to get a dodgy app running on a device. By borking KeyStore, some secure login functions could be accessed and master keys obtained.

The team notes that Google's KeyStore source code contains this harbinger of the vulnerability in the comments: "To keep things simple, buffers are always larger than the maximum space we needed, so boundary checks on buffers are omitted."

Unfortunately, applications can set the size of the data processed, meaning the buffers are not always large enough, and malicious software can therefore inject bytes into the KeyStore app's memory where it shouldn't. From there, the attacking code will try to hijack the flow of execution in KeyStore.

However, before people panic, the IBM advisory does explain that the flaw is a particularly tricky one to exploit.

An attacker would need to write an app that contained malware, convince the user to download and install it, and then evade multiple security defenses – DEP, ASLR and stack cookies – to exploit the buffer overflow and execute code within the KeyStore process. And even then some of the KeyStore information is still protected.

The IBM researchers found the flaw last September and alerted the Android security team privately about the issue. By November a fix was developed for Android 4.4, but not the Jelly Bean build, so the team sat on the problem a while longer before disclosing it.

"Considering Android’s fragmented nature and the fact that this was a code-execution vulnerability, we decided to wait a bit with the public disclosure," said Roee Hay, IBM's application security research team lead, in a blog post about the hole. ®

Internet Security Threat Report 2014

More from The Register

next story
Knock Knock tool makes a joke of Mac AV
Yes, we know Macs 'don't get viruses', but when they do this code'll spot 'em
Feds seek potential 'second Snowden' gov doc leaker – report
Hang on, Ed wasn't here when we compiled THIS document
Why weasel words might not work for Whisper
CEO suspends editor but privacy questions remain
DEATH by PowerPoint: Microsoft warns of 0-day attack hidden in slides
Might put out patch in update, might chuck it out sooner
BlackEnergy crimeware coursing through US control systems
US CERT says three flavours of control kit are under attack
prev story

Whitepapers

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.
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.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
Simplify SSL certificate management across the enterprise
Simple steps to take control of SSL across the enterprise, and recommendations for a management platform for full visibility and single-point of control for these Certificates.