Bafuputsi ba Univesithi ea Birmingham, eo pele e neng e tsejoa ka ho nts'etsapele litlhaselo tsa Plundervolt le VoltPillager, ba hlokometse ho ba kotsing (CVE-2022-43309) ho liboto tse ling tsa li-server tse lumellang CPU ho holofala 'meleng ntle le monyetla oa ho hlaphoheloa. Kotsi, e nang le codenamed PMFault, e ka sebelisoa ho senya lisebelisoa tseo mohlaseli a se nang phihlelo ea 'mele ho tsona, empa a na le monyetla oa ho fumana mokhoa oa ho sebetsa, o fumanoang, ka mohlala, ka ho sebelisa ts'oaetso e sa tsejoeng kapa ho thibela lintlha tsa molaoli.
Moko oa mokhoa o reriloeng ke ho sebelisa sebopeho sa PMBus, se sebelisang protocol ea I2C, ho eketsa motlakase o fuoang processor ho boleng bo bakang tšenyo ho chip. Khokahano ea PMBus hangata e kengoa tšebetsong ho VRM (Voltage Regulator Module), e ka fihlellehang ka ho qhekella ha molaoli oa BMC. Ho etsa tlhaselo ea mapolanka a tšehetsang PMBus, ntle le litokelo tsa batsamaisi tsamaisong ea ts'ebetso, o tlameha ho ba le phihlelo ea software ho BMC (Baseboard Management Controller), ka mohlala, ka IPMI KCS (Keyboard Controller Style) interface, ka tsela. Ethernet, kapa ka ho benya BMC ho tsoa ho sistimi ea hajoale.
Taba e lumellang tlhaselo hore e etsoe ntle le ho tseba liparamente tsa netefatso ho BMC e netefalitsoe ho liboto tsa bo-mme tsa Supermicro tse nang le tšehetso ea IPMI (X11, X12, H11 le H12) le ASRock, empa liboto tse ling tsa seva tse ka fihlellang PMBus le tsona li teng. amehang. Nakong ea liteko, ha motlakase o eketsoa ho 2.84 volts ho liboto tsena, li-processor tse peli tsa Intel Xeon li ile tsa senyeha. Ho fihlella BMC ntle le ho tseba liparamente tsa netefatso, empa ka phihlello ea metso ho sistimi ea ts'ebetso, ho ile ha sebelisoa ts'oaetso mochining oa netefatso ea firmware, e entseng hore ho khonehe ho kenya ntlafatso ea firmware e fetotsoeng ho molaoli oa BMC, hammoho le monyetla oa phihlello e sa netefatsoang ka IPMI KCS.
Mokhoa oa ho fetola motlakase ka PMBus o ka boela oa sebelisoa ho etsa tlhaselo ea Plundervolt, e lumellang, ka ho theola motlakase ho ea ho boleng bo fokolang, ho baka tšenyo ho likahare tsa lisele tsa data ho CPU e sebelisetsoang lipalo libakeng tse ka thōko tsa Intel SGX. le ho hlahisa liphoso ho li-algorithms tse nepahetseng qalong. Ka mohlala, haeba u fetola boleng bo sebelisitsoeng ho atisa nakong ea ts'ebetso ea encryption, tlhahiso e tla ba ciphertext e fosahetseng. Ka ho khona ho fihlella mohlokomeli ho SGX ho patala data ea eona, mohlaseli a ka khona, ka ho baka ho hloleha, ho bokella lipalo-palo mabapi le liphetoho tse hlahisoang ke ciphertext le ho fumana boleng ba senotlolo se bolokiloeng ka har'a SGX enclave.
Lisebelisoa tsa ho etsa tlhaselo ho liboto tsa Supermicro le ASRock, hammoho le ts'ebeliso ea ho lekola phihlello ea PMBus, li phatlalalitsoe ho GitHub.
Source: opennet.ru