Researchers use Intel SGX to put malware beyond the reach of antivirus software

Processor protects malware from attempts to inspect and analyze it.

Intel Skylake die shot.

Intel Skylake die shot. (credit: Intel)

Researchers have found a way to run malicious code on systems with Intel processors in such a way that the malware can't be analyzed or identified by antivirus software, using the processor's own features to protect the bad code. As well as making malware in general harder to examine, bad actors could use this protection to, for example, write ransomware applications that never disclose their encryption keys in readable memory, making it substantially harder to recover from attacks.

The research, performed at Graz University of Technology by Michael Schwarz, Samuel Weiser, and Daniel Gruss (one of the researchers behind last year's Spectre attack), uses a feature that Intel introduced with its Skylake processors called SGX ("Software Guard eXtensions"). SGX enables programs to carve out enclaves where both the code and the data the code works with are protected to ensure their confidentiality (nothing else on the system can spy on them) and integrity (any tampering with the code or data can be detected). The contents of an enclave are transparently encrypted every time they're written to RAM and decrypted upon being read. The processor governs access to the enclave memory: any attempt to access the enclave's memory from code outside the enclave is blocked; the decryption and encryption only occurs for the code within the enclave.

SGX has been promoted as a solution to a range of security concerns when a developer wants to protect code, data, or both, from prying eyes. For example, an SGX enclave running on a cloud platform could be used to run custom proprietary algorithms, such that even the cloud provider cannot determine what the algorithms are doing. On a client computer, the SGX enclave could be used in a similar way to enforce DRM (digital rights management) restrictions; the decryption process and decryption keys that the DRM used could be held within the enclave, making them unreadable to the rest of the system. There are biometric products on the market that use SGX enclaves for processing the biometric data and securely storing it such that it can't be tampered with.

Read 15 remaining paragraphs | Comments

Spectre, Meltdown researchers unveil 7 more speculative execution attacks

Systemic analysis reveals a range of new issues and a need for new mitigations.

Spectre, Meltdown researchers unveil 7 more speculative execution attacks

Enlarge (credit: Aurich Lawson / Getty Images)

Back at the start of the year, a set of attacks that leveraged the speculative execution capabilities of modern high-performance processors was revealed. The attacks were named Meltdown and Spectre. Since then, numerous variants of these attacks have been devised. In tandem, a range of mitigation techniques has been created to enable at-risk software, operating systems, and hypervisor platforms to protect against these attacks.

A research team—including many of the original researchers behind Meltdown, Spectre, and the related Foreshadow and BranchScope attacks—has published a new paper disclosing yet more attacks in the Spectre and Meltdown families. The result? Seven new possible attacks. Some are mitigated by known mitigation techniques, but others are not. That means further work is required to safeguard vulnerable systems.

The previous investigations into these attacks has been a little ad hoc in nature; examining particular features of interest to provide, for example, a Spectre attack that can be performed remotely over a network, or Meltdown-esque attack to break into SGX enclaves. The new research is more systematic, looking at the underlying mechanisms behind both Meltdown and Spectre and running through all the different ways the speculative execution can be misdirected.

Read 14 remaining paragraphs | Comments

Intel’s SGX blown wide open by, you guessed it, a speculative execution attack

Foreshadow explained in a video.[/url]
Another day, another speculative execution-based attack. Data protected by Intel’s SGX—data that’s meant to be protected even from a malicious or hacked kernel—can be read by an attacker thanks to leaks en…

Foreshadow explained in a video.[/url]

Another day, another speculative execution-based attack. Data protected by Intel's SGX—data that's meant to be protected even from a malicious or hacked kernel—can be read by an attacker thanks to leaks enabled by speculative execution.

Since publication of the Spectre and Meltdown attacks in January this year, security researchers have been taking a close look at speculative execution and the implications it has for security. All high-speed processors today perform speculative execution: they assume certain things (a register will contain a particular value, a branch will go a particular way) and perform calculations on the basis of those assumptions. It's an important design feature of these chips that's essential to their performance, and it has been for 20 years.

Read 22 remaining paragraphs | Comments

New Spectre attack enables secrets to be leaked over a network

Enlarge (credit: Pete)

When the Spectre and Meltdown attacks were disclosed earlier this year, the initial exploits required an attacker to be able to run code of their choosing on a victim system. This made browsers vulnerable, as suitably crafted…

Enlarge (credit: Pete)

When the Spectre and Meltdown attacks were disclosed earlier this year, the initial exploits required an attacker to be able to run code of their choosing on a victim system. This made browsers vulnerable, as suitably crafted JavaScript could be used to perform Spectre attacks. Cloud hosts were susceptible, too. But outside these situations, the impact seemed relatively limited.

That impact is now a little larger. Researchers from Graz University of Technology, including one of the original Meltdown discoverers, Daniel Gruss, have described NetSpectre: a fully remote attack based on Spectre. With NetSpectre, an attacker can remotely read the memory of a victim system without running any code on that system.

All the variants of the Spectre attacks follow a common set of principles. Each processor has an architectural behavior (the documented behavior that describes how the instructions work and that programmers depend on to write their programs) and a microarchitectural behavior (the way an actual implementation of the architecture behaves). These can diverge in subtle ways. For example, architecturally, a program that loads a value from a particular address in memory will wait until the address is known before trying to perform the load. Microarchitecturally, however, the processor might try to speculatively guess at the address so that it can start loading the value from memory (which is slow) even before it's absolutely certain of which address it should use.

Read 11 remaining paragraphs | Comments