So here is #spectre variant 4. The processor speculates that your write operation does not change anything and continues with the outdated (possibly non-sanitized) value from L1.https://t.co/ZcjaTSrLNW

— Daniel Gruss (@lavados) May 21, 2018

#spectreng Details on 2 / 8 vuls: v3a (Rogue SRR, CVE-2018-3640) https://t.co/MhKvqALGcu & v4 (SSB, CVE-2018-3639) https://t.co/lpohRw2GFP [Intel, ARM, IBM POWER; ucode patches in beta but no update dates announced, disabling v4 Memory Disambiguation incurs 2-8% perf overhead] pic.twitter.com/voILONMMeY

— Daniel Bilar (@daniel_bilar) May 22, 2018

Variant 4 and 3a have dropped, with the appropriate Intel Whitepaper updates. The RSRE one is the coolest one to me. https://t.co/56AbOoK159 https://t.co/2JYWWzAC5g

— Alex Ionescu (@aionescu) May 21, 2018

speculative execution, variant 4: speculative store bypass https://t.co/z1ZlS1HNxU

— Project Zero Bugs (@ProjectZeroBugs) May 21, 2018

A small observation: the current set of speculative execution fixes are replicating at an architectural level what extensions are at the ISA level.

Byzantine Security, one level down.

— Arrigo Triulzi (@cynicalsecurity) May 22, 2018

Speculative Execution is fundamentally broken in its current trust model.

— Arrigo Triulzi (@cynicalsecurity) May 22, 2018