What is row hammer in DRAM?
Rowhammer is a vulnerability in commodity dynamic random access memory (DRAM) chips that allows an attacker to exploit devices with DRAM memory by repeatedly accessing (hammering) a row of memory until it causes bit flips and transistors in adjacent rows of memory reverse their binary state: ones turn into zeros and …
What makes Rowhammer attacks possible?
The opportunity for the row hammer effect to occur in DDR3 memory is primarily attributed to DDR3’s high density of memory cells and the results of associated interactions between the cells, while rapid DRAM row activations have been determined as the primary cause.
Why does Rowhammer work?
Rowhammer attacks work by rapidly and repeatedly reading data in one memory row to cause an electrical charge in adjacent memory rows in order to modify or corrupt data.
What is Target row refresh?
Among existing solutions, the leading and most effective example is the Target Row Refresh (TRR) mechanism. TRR is proposed as the standard protection mechanism by JEDEC [1] and is widely used in DDR4 memory. As a protection scheme, TRR will refresh the victim row once a Rowhammer attack is detected.
How do you stop RowHammer?
One straightforward solution to mitigate row-hammer is to simply increase the refresh rate for all the rows in the memory system. Although, this approach might alleviate the Row Hammer error, it imposes an unnecessary power and performance overhead to the system.
What is a RowHammer vulnerability?
RowHammer is a circuit-level DRAM vulnerability where re- peatedly accessing (i.e., hammering) a DRAM row can cause bit flips in physically nearby rows. The RowHammer vulnerability worsens as DRAM cell size and cell-to-cell spacing shrink.
What are the potential mitigation solutions for row hammer?
What is Plundervolt?
Plundervolt is a method of hacking that involves depriving an Intel chip of power so that processing errors occur. These errors can expose sensitive data and weaken chip security components.
Is Rowhammer a side channel?
Rowhammer is an attack technique involving accessing—that’s “hammering”—rows of bits in memory, millions of times per second, with the intent of causing bits in neighboring rows to flip. This is a side-channel attack, and the result can be all sorts of mayhem.
How does Spectre and meltdown work?
What are Spectre and Meltdown? In the most basic definition, Spectre is a vulnerability allowing for arbitrary locations in the allocated memory of a program to be read. Meltdown is a vulnerability allowing a process to read all memory in a given system.
How often does DRAM need to be refreshed?
every 64 ms
Refresh cycle time among different density. In the JEDEC standard [2], DRAM cells are refreshed every 64 ms at normal temperature (<85 °C) and 32 ms at high temperature (>85 °C).
What is Spectre and meltdown vulnerability?
Spectre and Meltdown are uniquely dangerous security vulnerabilities that allow malicious actors to bypass system security protections present in nearly every recent device with a CPU-not just PCs, servers, and smartphones, but also Internet of Things (IoT) devices like routers and smart TVs.
How do you protect against RowHammer?
Should I be worried about Plundervolt?
Should I worry about Plundervolt if my enclave does not perform cryptographic operations? Yes. In addition to the extraction of cryptographic keys, Plundervolt can also cause memory safety misbehaviour in certain scenarios.
Is Plundervolt fixed?
Intel has quickly released a fix for the new and already infamous Plundervolt vulnerability found in Intel 6th, 7th, 8th, 9th, and 10th generation processors, alongside Xeon Processor E3 v5 and v6, and Xeon Processor E-2100 and E-2200.
Has Spectre been fixed?
In March 2018, Intel announced that they had developed hardware fixes for Meltdown and Spectre-V2 only, but not Spectre-V1. The vulnerabilities were mitigated by a new partitioning system that improves process and privilege-level separation.
Has Spectre been exploited?
A fully weaponized exploit for the Spectre CPU vulnerability was uploaded on the malware-scanning website VirusTotal last month, marking the first time a working exploit capable of doing actual damage has entered the public domain. The exploit was discovered by French security researcher Julien Voisin.
Is DRAM faster than SRAM?
SRAM stands for Static Random Access Memory. It does not have to be refreshed with electric charge. It is faster than DRAM because the CPU does not have to wait to access data from SRAM. SRAM chips utilise less power and are more complex to create, making it much more expensive than DRAM.
Is Spectre patched?
Spectre is a hardware vulnerability and CPU vendors including Intel and AMD released patches to mitigate the risks of Spectre. The patch was essentially a small bit of software that updated the CPU microcode.