Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Cloud Security //

Google

8/20/2018
09:05 AM
Larry Loeb
Larry Loeb
Larry Loeb
50%
50%

Foreshadow-NG Vulnerability Sets Tech Giants Scrambling

Foreshadow vulnerabilities expose processors and even the cloud to penetration.

In early January, the Spectre and Meltdown vulnerabilities were disclosed to the computer world, which promptly lost its shirt for a period. This was a new class of attacks that depended on the way that modern processors shoved data in and out of the CPU, a process that was never thought to be problematic.

Eventually, patches and mitigations for these potential attacks were developed and installed. A sigh of relief arose from everyone in the field.

But everyone was wrong. The problem was more complex and destructive than it appeared.

It turns out that when Spectre was announced, some other researchers (two teams of them, actually) found that the problem was much deeper than it seemed. It went deep enough to threaten the supposedly secure data enclaves on the chip (Intel calls it SGX) that were there to stop one part of memory from accessing another more secure part of the same memory.

The researchers call the hole “Foreshadow.” This kind of SGX access was previously thought not to be possible in the Spectre and Meltdown problems.

Wait, it gets worse.

As Intel looked deeper, they realized this was bigger than just SGX. Intel and that second team found a variant of the original attack dubbed Foreshadow-Next Generation (NG) (PDF) that could expose information stored in the processor’s L1 cache (the one that is architecturally closest to the activity in the CPU), as well as information associated with the SMM, the operating system’s kernel, and hypervisors. It could also affect processors besides those of Intel.

So, there are multiple problems that have been admitted by Intel.

There is CVE-2018-3615 (the original SGX one), CVE-2018-3620, that opens up operating systems and System Management Mode (SMM), and CVE-2018-3646 affecting virtualization software and Virtual Machine Monitors (VMM).

Intel thinks that, taken together, the impact is huge. The company summarizes what it thinks in four points:

  1. Malicious applications may be able to infer the values of data in the operating system memory or data from other applications.
  2. A malicious guest virtual machine (VM) may be able to infer the values of data in the VMM’s memory or values of data in the memory of other guest VMs.
  3. Malicious software running outside of SMM may be able to infer values of data in SMM memory.
  4. Malicious software running outside of an SGX enclave or within an enclave may be able to infer data from within another SGX enclave.

If you let that sink it, it means that virtual machines -- the kind that run in the cloud -- are at risk.

Not only that, but the microcode updates that Intel has done to mitigate will not be enough by itself. The OS as well as the hypervisor controlling those cloud machines will need to be patched or updated.

Boy howdy, this is now some big-time aggravation.

Microsoft has an advisory out there that speaks about the way it is plugging holes in Azure. Google also says it’s doing the same for its cloud, as does Amazon for AWS.

Software vendors are also scrambling to patch their software to reflect this situation.

The true solution is going to require new CPU hardware that does things differently, not just some kludge that protects against known attacks. Those CPUs may be under development, as Intel says, but they’re not here yet.

Related posts:

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 9/25/2020
Hacking Yourself: Marie Moe and Pacemaker Security
Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
Startup Aims to Map and Track All the IT and Security Things
Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-15208
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
CVE-2020-15209
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
CVE-2020-15210
PUBLISHED: 2020-09-25
In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
CVE-2020-15211
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
CVE-2020-15212
PUBLISHED: 2020-09-25
In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...