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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2020.2011 Xen: Special Register Buffer speculative side channel vulnerability 10 June 2020 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Xen Publisher: Xen Operating System: Windows UNIX variants (UNIX, Linux, OSX) Virtualisation Impact/Access: Access Privileged Data -- Existing Account Resolution: Patch/Upgrade CVE Names: CVE-2020-0543 Reference: ESB-2020.2005 ESB-2020.2003 ESB-2020.1999 ESB-2020.1994 Original Bulletin: http://xenbits.xen.org/xsa/advisory-320.html - --------------------------BEGIN INCLUDED TEXT-------------------- - -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Xen Security Advisory CVE-2020-0543 / XSA-320 Special Register Buffer speculative side channel ISSUE DESCRIPTION ================= This issue is related to the MDS and TAA vulnerabilities. Please see https://xenbits.xen.org/xsa/advisory-297.html (MDS) and https://xenbits.xen.org/xsa/advisory-305.html (TAA) for details. Certain processor operations microarchitecturally need to read data from outside the physical core (e.g. to communicate with the random number generator). In some implementations, this operation is called a Special Register Read. In some implementations, data are staged in a single shared buffer, and a full cache line at a time is returned to the core which made the Special Register Read. On parts vulnerable to MFBDS or TAA, an attacker may be able to access stale data requested by other cores in the system. For more details, see: https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00320.html IMPACT ====== An attacker, which could include a malicious untrusted user process on a trusted guest, or an untrusted guest, can sample the contents of certain off-core accesses by other cores in the system. This can include data whose use may depend on the secrecy of the value, such as data from the Random Number Generator (e.g. RDRAND/RDSEED instructions). VULNERABLE SYSTEMS ================== Systems running all versions of Xen are affected. Only x86 processors are vulnerable. ARM processors are not believed to be vulnerable. Only Intel based processors are affected. Processors from other manufacturers (e.g. AMD) are not believed to be vulnerable. Please consult the Intel Security Advisory for details on the affected processors. MITIGATION ========== There is no mitigation available. RESOLUTION ========== New microcode is being released on affected parts to work around the vulnerability. It may be available via a firmware update (consult your hardware vendor), or available for OS loading (consult your dom0 OS vendor). On Xen 4.13 and later, OS microcode can be loaded at runtime. See https://xenbits.xen.org/docs/latest/admin-guide/microcode-loading.html#runtime-microcode-loading for details on the xen-ucode utility. Loading the microcode, either at boot or at runtime, suffices to mitigate the issue, as protections are active by default. The mitigations do have an impact on latency of individual RDRAND/RDSEED instructions. The patches below are for Xen, and offer boot time information, defaults selection, and opt-out controls. They are recommended to take, but not absolutely necessary for protection. Note that patches for released versions are generally prepared to apply to the stable branches, and may not apply cleanly to the most recent release tarball. Downstreams are encouraged to update to the tip of the stable branch before applying these patches. xsa320/xsa320-.patch xen-unstable xsa320/xsa320-4.13-.patch Xen 4.13.x xsa320/xsa320-4.12-.patch Xen 4.12.x xsa320/xsa320-4.11-.patch Xen 4.11.x xsa320/xsa320-4.10-.patch Xen 4.10.x xsa320/xsa320-4.9-.patch Xen 4.9.x $ sha256sum xsa320*/* 84e4f66492042b08e69b0894ea7feb20c17c89a696cf95f05a8826fba4f26355 xsa320/xsa320-1.patch 5a3a06c72d0281fa1191ba18e39b836d2748400d9bf6a59dd45447850530c88b xsa320/xsa320-2.patch 759259ef88c980363d44e11d9c272f6a4a15918e5e6bcdfe971b1ce7ea160cd9 xsa320/xsa320-4.9-1.patch ebac2c011841c55c3c1e99d9e8afc53e56e54268d379ec8b904f6bfe6a1a5045 xsa320/xsa320-4.9-2.patch 5c622c74358ab21cbd27484c649f26df0f08e89ec333c346415bc51e35ba26c1 xsa320/xsa320-4.10-1.patch f112e34a6a4564a043926fc255a15c7e319001bd023a97ae2947228024e1c306 xsa320/xsa320-4.10-2.patch f24b51292be0cb5de80c6eff0b26983629dd48cc39ae5a331e2e38e15a6cf712 xsa320/xsa320-4.11-1.patch 03579810eaf2e9eeb1a82de4b50ff5c4b01e60b30ccf7609c9e3378ef576d81e xsa320/xsa320-4.11-2.patch 282537ffe2fd4332c0e061ddc537bea3e135a7bbd9253ec298becb49047323cf xsa320/xsa320-4.12-1.patch e4417429297354c233e8f5c261aff4888aae602f8c68897c09b16ea1aa44b1ca xsa320/xsa320-4.12-2.patch 611f2ab1a1c67e04767188d9803b6afd7d304e81a5b4f1eb1744d3e8a68ced66 xsa320/xsa320-4.13-1.patch cd1bc0071e72e2342ff4508ea3d937988694f4c03506b3afb3184f7d81aa1c86 xsa320/xsa320-4.13-2.patch $ NOTE REGARDING LACK OF EMBARGO ============================== Despite an attempt to organise predisclosure, the discoverers ultimately did not authorise a predisclosure. - -----BEGIN PGP SIGNATURE----- iQFABAEBCAAqFiEEI+MiLBRfRHX6gGCng/4UyVfoK9kFAl7fufEMHHBncEB4ZW4u b3JnAAoJEIP+FMlX6CvZCNgIALz6dLCvvznL7n3HFzYgKcelmOySjoZ52hJhg6ki N4C1AaPQmo1QPprycmuJ4uQIcLUP55Nh+h19V5PnRqSX1+7Qa8TXnv2TTpVK58fC JBfWBZ3xiXYdmaQOWYlJtD1Nq3vywA0LII9TZ7JdCUxjmPxn2y5ZOv6lRG6P9CVJ U+w3py0Zt32ZwYvVCbBPP49SdQmArH2BItEbGSQR5xeKnD/8Bx2/9odN0Mrnq5RQ euJxRled3nCGw6tWZJj3uYOy+dWWfmFwPFoFvI++zhrcwWGprcgjFuSGFbsGttMD ZB9+CZIJAHvgU4wu/B4SflHDgsmJS+iCmDR6e/NUlLohej0= =w+E7 - -----END PGP SIGNATURE----- - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. 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It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://www.auscert.org.au/bulletins/ =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBXuBfxuNLKJtyKPYoAQhkjg/+KAmoCYDUwwET8pW+2/NGDjYhzAqLGyEZ aNvOcbF1Yoj5OD+CEaTItm913WTOzKlSuqeNR7rsVwXJI1VYeyx1pCNzxCb9mQE+ cUsQ48EsNWA7pNOan3A5SDhbFBbNEGidfqOOq3X/GNa6Om8EH3MgXmevwyO+rrM5 8vJaYQZ+ksWc4PwcRuNYYQ5aYIGVej+KysUlyHAdxzSDmW/SBrFhEe0kMJT0NuEh f7YR+O5v5A3ND2No+GHkJH8ZCZZqkXj6DT66Jd/UzobFOqOJDYhkaYm+K3DOlP1h jkl4Q+smtJB4eHv5InVz4P5xDfuJTwU3XY02MwK0dv/0xccf9zRGjc0CffI1PVGa LtkAYPqwIQzHzpZV3UWYUxcZYb21JkQwpW1Wcvn5dPtyol50xM16cjzE0iTpXNKA tUl35fDnaQ+WdqH8yVmTF5E6//JPAJ3mT4n8EjRcLBARUOWivTodHAnvPpqLYUnr IrQ7jpJqtlpOgB30OYmA+k9CNtTugqTb6SEzXYY+cbH77h4XnuoQVJi9fZHSCR6y NHo8GWrsUcQQjLYoOWITf2996wPNbD3S9m8KDf0/jn44EBCk+VEbgpKjKpxep+eZ EGaMLN5WiQteLGYdqVMFqMu1DLegCDdhSz3QAewrjpC1Auz0QCJrCAqk1dzSTa4o WTyUulMlOls= =po1z -----END PGP SIGNATURE-----