2018-01-07 15:00:59 +01:00
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Spectre & Meltdown Checker
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A simple shell script to tell if your Linux installation is vulnerable
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against the 3 "speculative execution" CVEs:
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CVE-2017-5753 bounds check bypass (Spectre Variant 1)
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Impact: Kernel & all software
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Mitigation: recompile software *and* kernel with a modified compiler that introduces the LFENCE opcode at the proper positions in the resulting code
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Performance impact of the mitigation: negligible
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CVE-2017-5715: branch target injection (Spectre Variant 2)
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Impact: Kernel
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Mitigation 1: new opcode via microcode update that should be used by up to date compilers to protect the BTB (by flushing indirect branch predictors)
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Mitigation 2: introducing "retpoline" into compilers, and recompile software/OS with it
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Performance impact of the mitigation: high for mitigation 1, medium for mitigation 2, depending on your CPU
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CVE-2017-5754: rogue data cache load (Meltdown)
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Impact: Kernel
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Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough
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Performance impact of the mitigation: low to medium
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Example of the output of the script:
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Spectre and Meltdown mitigation detection tool v0.01
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CVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'
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* Kernel recompiled with LFENCE opcode insertion: UNKNOWN (check not yet implemented)
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> STATUS: UNKNOWN (not implemented, but real answer is most probably VULNERABLE at this stage)
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CVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'
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* Mitigation 1
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* Hardware (CPU microcode) support for mitigation: NO
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* Kernel support for IBRS: NO
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* IBRS enabled for Kernel space: NO
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* IBRS enabled for User space: NO
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* Mitigation 2
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* Kernel recompiled with retpoline: UNKNOWN (check not yet implemented)
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> STATUS: VULNERABLE (IBRS hardware + kernel support OR retpoline-compiled kernel are needed to mitigate the vulnerability)
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CVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'
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* Kernel supports Page Table Isolation (PTI): YES
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* PTI enabled and active: YES
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> STATUS: NOT VULNERABLE (PTI mitigates the vulnerability)
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