me.mello Posted June 21, 2012 Report Posted June 21, 2012 (edited) Cine ar fi crezut Intel...sau hardware in general...sistemele pe 32 biti sunt momentan sigure...insa cele pe 64 sunt in general vulnerabile.SYSRET 64-bit operating system privilege escalation vulnerability on Intel CPU hardwareThe U.S. Computer Emergency Readiness Team (US-CERT) has disclosed a flaw in Intel chips that could allow hackers to gain control of Windows and other operating systems.The flaw has already been exploited on 64-bit versions of Microsoft Windows 7, FreeBSD, NetBSD and there’s a chance Apple’s OS X may also be vulnerable.The flaw was disclosed the vulnerability in a security advisory released this week. Attackers could execute malicious code via kernel privileges or launch a local privilege escalation attack. VMware's virtualization software is not affected, and neither are AMD's processors, as they do not use the SYSRET instruction whose incorrect handling causes the flaw or handle it differently.Many of the affected vendors have already pushed out an update that defuses the flaw.Reff: Intel CPU Vulnerability can provide control of your system to attacker | The Hacker NewsOverviewSome 64-bit operating systems and virtualization software running on Intel CPU hardware are vulnerable to a local privilege escalation attack. The vulnerability may be exploited for local privilege escalation or a guest-to-host virtual machine escape.Intel claims that this vulnerability is a software implementation issue, as their processors are functioning as per their documented specifications. However, software that fails to take the Intel-specific SYSRET behavior into account may be vulnerable.DescriptionA ring3 Ring (computer security) - Wikipedia, the free encyclopedia attacker may be able to specifically craft a stack frame to be executed by ring0 (kernel) after a general protection exception (#GP). The fault will be handled before the stack switch, which means the exception handler will be run at ring0 with an attacker's chosen RSP causing a privilege escalation.Details from XenCVE-2012-0217 / XSA-7 - 64-bit PV guest privilege escalation vulnerability [Xen-announce] Xen Security Advisory 7 (CVE-2012-0217) - PV privilege escalationA vulnerability which can allow a 64-bit PV guest kernel running on a 64-bit hypervisor to escalate privileges to that of the host by arranging for a system call to return via sysret to a non-canonical RIP. Intel CPUs deliver the resulting exception in an undesirable processor state.Details from FreeBSDFreeBSD-SA-12:04.sysret: Privilege escalation when returning from kernel http://security.freebsd.org/advisories/FreeBSD-SA-12:04.sysret.ascFreeBSD/amd64 runs on CPUs from different vendors. Due to varying behaviour of CPUs in 64 bit mode a sanity check of the kernel may be insufficient when returning from a system call. Successful exploitation of the problem can lead to local kernel privilege escalation, kernel data corruption and/or crash.Details from MicrosoftUser Mode Scheduler Memory Corruption Vulnerability - MS12-042 - Important Microsoft Security Bulletin MS12-042 - Important : Vulnerabilities in Windows Kernel Could Allow Elevation of Privilege (2711167)An elevation of privilege vulnerability exists in the way that the Windows User Mode Scheduler handles system requests. An attacker who successfully exploited this vulnerability could run arbitrary code in kernel mode. An attacker could then install programs; view, change, or delete data; or create new accounts with full administrative rights.Mitigating Factors for User Mode Scheduler Memory Corruption VulnerabilityMitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors may be helpful in your situation: An attacker must have valid logon credentials and be able to log on locally to exploit this vulnerability. The vulnerability could not be exploited remotely or by anonymous users. This vulnerability only affects Intel x64-based versions of Windows 7 and Windows Server 2008 R2. Systems with AMD or ARM-based CPUs are not affected by this vulnerability.Details from Red HatRHSA-2012:0720-1 https://rhn.redhat.com/errata/RHSA-2012-0720.html & RHSA-2012:0721-1 https://rhn.redhat.com/errata/RHSA-2012-0721.html : It was found that the Xen hypervisor implementation as shipped with Red Hat Enterprise Linux 5 did not properly restrict the syscall return addresses in the sysret return path to canonical addresses. An unprivileged user in a 64-bit para-virtualized guest, that is running on a 64-bit host that has an Intel CPU, could use this flaw to crash the host or, potentially, escalate their privileges, allowing them to execute arbitrary code at the hypervisor level. (CVE-2012-0217, Important)Details from some affected vendors were not available at the time of publication.ImpactA local authenticated attacker may exploit this vulnerability for operating system privilege escalation or for a guest-to-host virtual machine escape.SolutionApply an UpdatePlease review the Vendor Information section of this document for vendor-specific patch and workaround details.Vendor Information: Vendor Status Date Notified Date UpdatedCitrix Affected - 18 Jun 2012FreeBSD Project Affected 01 May 2012 12 Jun 2012Intel Corporation Affected 01 May 2012 13 Jun 2012Joyent Affected - 14 Jun 2012Microsoft Corporation Affected 01 May 2012 18 Jun 2012NetBSD Affected 01 May 2012 08 Jun 2012Oracle Corporation Affected 01 May 2012 08 Jun 2012Red Hat, Inc. Affected 01 May 2012 12 Jun 2012SUSE Linux Affected 02 May 2012 12 Jun 2012Xen Affected 02 May 2012 12 Jun 2012AMD Not Affected - 13 Jun 2012Apple Inc. Not Affected 01 May 2012 08 Jun 2012VMware Not Affected 01 May 2012 08 Jun 2012Debian GNU/Linux Unknown 02 May 2012 02 May 2012Fedora Project Unknown 02 May 2012 02 May 2012Sursa: US-CERT Vulnerability Note VU#649219 - SYSRET 64-bit operating system privilege escalation vulnerability on Intel CPU hardware Edited June 21, 2012 by me.mello 1 Quote
