Feeds

'Super-secret' debugger discovered in AMD CPUs

Password-protected feature goes beyond x86

SANS - Survey on application security programs

A hardware hacker has discovered a secret debugging feature hidden in all AMD chips made in the past decade.

The password-protected debugger came as a shock to reverse-engineers who have hungered for an on-chip mechanism for performing conditional and direct-hardware breakpoint operations. Although AMD has built the firmware-controlled feature into all chips since the Athlon XP, the company kept it a closely guarded secret that was only disclosed late last week by a hacker who goes by the name Czernobyl.

“AMD processors (Athlon XP and better) have included firmware-based debugging features that expand greatly over standard, architecturally defined capabilities of x86,” the hacker wrote. “For some reason, though, AMD has been tightly secretive about these features; hint of their existence was gained by glancing at CBID's page.”

To put a chip into developer mode, a user must first enter what amounts to a password — 9C5A203A — into the CPU's EDI register. Czernobyl was able to deduce the secret setting by brute forcing the key.

Presumably, the debugger is an internal AMD utility used during development and then turned off before shipping. Its discovery by world + dog means that everyday users may have powerful new tools to hack, debug, and reverse-engineer their hardware. Now that its existence and the instructions for turning it on are known, the real discoveries about exactly what can be done with it are sure to commence. ®

Combat fraud and increase customer satisfaction

More from The Register

next story
WTF happened to Pac-Man?
In his thirties and still afraid of ghosts
Reg man builds smart home rig, gains SUPREME CONTROL of DOMAIN – Pics
LightwaveRF and Arduino: Bright ideas for dim DIYers
Leaked pics show EMBIGGENED iPhone 6 screen
Fat-fingered fanbois rejoice over Chinternet snaps
Apple patent LOCKS drivers out of their OWN PHONES
I'm sorry Dave, I'm afraid I can't let you text that
Microsoft signs Motorola to Android patent pact – no, not THAT Motorola
The part that Google never got will play ball with Redmond
Slip your finger in this ring and unlock your backdoor, phone, etc
Take a look at this new NFC jewellery – why, what were you thinking of?
Happy 25th birthday, Game Boy!
Monochrome handset ushered in modern mobile gaming era
Rounded corners? Pah! Amazon's '3D phone has eye-tracking tech'
Now THAT'S what we call a proper new feature
Zucker punched: Google gobbles Facebook-wooed Titan Aerospace
Up, up and away in my beautiful balloon flying broadband-bot
prev story

Whitepapers

Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Securing web applications made simple and scalable
In this whitepaper learn how automated security testing can provide a simple and scalable way to protect your web applications.
Combat fraud and increase customer satisfaction
Based on their experience using HP ArcSight Enterprise Security Manager for IT security operations, Finansbank moved to HP ArcSight ESM for fraud management.