Date: Thu, 26 Nov 2020 16:44:45 +0000 From: Xen.org security team <security@....org> To: xen-announce@...ts.xen.org, xen-devel@...ts.xen.org, xen-users@...ts.xen.org, oss-security@...ts.openwall.com CC: Xen.org security team <security-team-members@....org> Subject: Xen Security Advisory 351 v2 (CVE-2020-28368) - Information leak via power sidechannel -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Xen Security Advisory CVE-2020-28368 / XSA-351 version 2 Information leak via power sidechannel UPDATES IN VERSION 2 ==================== CVE assigned. ISSUE DESCRIPTION ================= Researchers have demonstrated using software power/energy monitoring interfaces to create covert channels, and infer the operations/data used by other contexts within the system. Access to these interfaces should be restricted to privileged software, but it was found that Xen doesn't restrict access suitably, and the interfaces are accessible to all guests. For more information, see: https://platypusattack.com https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00389.html IMPACT ====== An unprivileged guest administrator can sample platform power/energy data. This may be used to infer the operations/data used by other contexts within the system. The research demonstrates using this sidechannel to leak the AES keys used elsewhere in the system. VULNERABLE SYSTEMS ================== Power/energy monitoring interfaces are platform and architecture specific. Consult your hardware vendor to ascertain what power feedback interfaces are available. For ARM systems, all versions of Xen are vulnerable. The fix restricts access to the AMU (Activity Monitors Unit) interface, introduced in Armv8.4. For x86 systems, Xen 4.14 and earlier are vulnerable - master is not vulnerable, as these issues have been addressed in a more general fashion. The x86 fixes restrict access to: * Intel RAPL interface, introduced in SandyBridge CPUs. * Intel platform energy interface. * Intel perf_ctl interface, introduced in Pentium 4 CPUs and also implemented by other vendors. * AMD RAPL interface, introduced in Ryzen/EPYC CPUs. * AMD compute unit energy interface, present in Fam15/16 CPUs. MITIGATION ========== There are no mitigations available. RESOLUTION ========== Applying the appropriate attached patch resolves this issue. 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. xsa351-arm.patch Xen unstable - 4.10.x [ARM] xsa351-x86-4.14-?.patch Xen 4.14.x [x86] xsa351-x86-4.13-?.patch Xen 4.13.x [x86] xsa351-x86-4.12-?.patch Xen 4.12.x [x86] xsa351-x86-4.11-?.patch Xen 4.11.x - 4.10.x [x86] $ sha256sum xsa351* cad287981a870f13484834fa2364ffee68178517e906f55d2889304a4a9eae06 xsa351.meta 70ebd0e93af240af2680374dcfd8ff4a5dd3eefccf670f1cb9b546d763d6a554 xsa351-arm.patch 49b52a1366912a29e184e3014a9f1f579e8a0dd8a36f01d38d995d2c8ed81928 xsa351-arm-4.11.patch 2e7b7c2b98625d70c8b10047a9f668372f3ccede167344dedb712312606acbca xsa351-x86-4.11-1.patch ab9e2cb7d5e3e0c3a916f006c697495f4f01146e09df60ece59ce0a8f7aa5ed0 xsa351-x86-4.11-2.patch bb68f6e6905bc1566156cafab058cbaf02a17c197385c33a83b7f73885913c1c xsa351-x86-4.12-1.patch 53f464269f59498f8a9a614f10a47cfb1d81c666f0d684346e28005015de962c xsa351-x86-4.12-2.patch 67a29d66230faafd9a8047ac80ec18130b5659e80a38c3a412cb2be6d3288a8f xsa351-x86-4.13-1.patch f7d8717dec33ee7484b36490402d113f1e7e168e7541bcf193fef620df299f08 xsa351-x86-4.13-2.patch 7d4fbe11a766226d7f1b93c5bf34664d8855deee09d1feebc76f11e49f2aa9c9 xsa351-x86-4.14-1.patch 41df825deafe3ef28e8594ec956033689af69f84a4a6dd92f97d1071e925203d xsa351-x86-4.14-2.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/4UyVfoK9kFAl+/22UMHHBncEB4ZW4u b3JnAAoJEIP+FMlX6CvZt0IH/1P4OlmyExkX0u1mVXcG3o85esBYDAD6RKDhRCr5 IjbitMUItESGYyz/Z6BEmuUIiJ1gfNx7xs4I3b4i8UUBYdBvvsdjeL3WK75Ym3nW Jh63AQzbDeNjkEnK4UnF6+V/9BJJUYB4avH6m82LU8+9Gp8S9CGH4y73gpiTGhcK VHPhdPOSc+ZDJ/OEQUR/3uMci9nuQ+qw9PClGybj3j4iru3PWfPRCSsdy2sAZO0T KwS+PvDgFKWqKiIAL6Ahfb0VnREP8zqpIxSq2cN8+SuVQym+H6zKh2exvYtEjq/j pWNzHublyLZoSBLvfguIeNKj4x2va9dF7/jJAnLfNVrvJCI= =QgHs -----END PGP SIGNATURE----- Download attachment "xsa351.meta" of type "application/octet-stream" (1772 bytes) Download attachment "xsa351-arm.patch" of type "application/octet-stream" (2418 bytes) Download attachment "xsa351-arm-4.11.patch" of type "application/octet-stream" (2714 bytes) Download attachment "xsa351-x86-4.11-1.patch" of type "application/octet-stream" (6244 bytes) Download attachment "xsa351-x86-4.11-2.patch" of type "application/octet-stream" (4448 bytes) Download attachment "xsa351-x86-4.12-1.patch" of type "application/octet-stream" (5992 bytes) Download attachment "xsa351-x86-4.12-2.patch" of type "application/octet-stream" (4682 bytes) Download attachment "xsa351-x86-4.13-1.patch" of type "application/octet-stream" (5988 bytes) Download attachment "xsa351-x86-4.13-2.patch" of type "application/octet-stream" (4800 bytes) Download attachment "xsa351-x86-4.14-1.patch" of type "application/octet-stream" (6075 bytes) Download attachment "xsa351-x86-4.14-2.patch" of type "application/octet-stream" (5173 bytes)
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