It was found that a malicious HVM guest administrator can cause DoS, specifically prevent use of physical CPU for significant, perhaps indefinite period. When a benign exception occurs while delivering another benign exception, it is architecturally specified that these would be delivered sequentially. There are, however, cases where this results in an infinite loop inside the CPU, which (in the virtualized case) can be broken only by intercepting delivery of the respective exception.
When a guest sets up a hardware breakpoint covering a data structure involved in delivering #DB (Debug Exception), upon completion of the delivery of the first exception another #DB will need to be delivered. The effects slightly differ depending on further guest characteristics:
Guests running in 32-bit mode would be expected to sooner or later encounter another fault due to the stack pointer decreasing during each iteration of the loop. The most likely case would be #PF (Page Fault) due to running into unmapped virtual space. However, an infinite loop cannot be excluded (e.g. when the guest is running with paging disabled).
Guests running in long mode, but not using the IST (Interrupt Stack Table) feature for the IDT entry corresponding to #DB would behave similarly to guests running in 32-bit mode, just that the larger virtual address space allows for a much longer loop. The loop can't, however, be infinite, as eventually the stack pointer would move into non-canonical address space, causing #SS (Stack Fault) instead.
Guests running in long mode and using the IST for the IDT entry corresponding to #DB would enter an infinite loop, as the stack pointer wouldn't change between #DB instances.
If a host watchdog (Xen or dom0) is in use, this can lead to a watchdog timeout and consequently a reboot of the host. If another, innocent, guest, is configured with a watchdog, this issue can lead to a reboot of such a guest.
A privileged user inside guest could use this flaw to crash the host kernel resulting in DoS.
For KVM virtualisation, it only affects the AMD processor support, as for Intel it already intercepts the #DB exception.
Upstream KVM patch: ------------------- -> http://permalink.gmane.org/gmane.linux.kernel/2082332
References: ----------- -> http://www.openwall.com/lists/oss-security/2015/11/10/1
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.0 Base Score 8.8 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Difficult to exploit vulnerability allows high privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.0 Base Score 7.5 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H).
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Difficult to exploit vulnerability allows high privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.0 Base Score 7.5 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H).
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Easily exploitable vulnerability allows high privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in takeover of Oracle VM VirtualBox. CVSS 3.0 Base Score 8.2 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).
This vulnerability allows local attackers to escalate privileges on affected installations of Oracle VirtualBox. An attacker must first obtain the ability to execute high-privileged code on the target guest system in order to exploit this vulnerability. The specific flaw exists within the shadergetregistersused function. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated object. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the hypervisor.
Unspecified vulnerability in the Oracle VM VirtualBox component before 5.0.28 and 5.1.x before 5.1.8 in Oracle Virtualization allows local users to affect confidentiality, integrity, and availability via vectors related to Core, a different vulnerability than CVE-2016-5538.
Unspecified vulnerability in the Oracle VM VirtualBox component before 5.0.28 and 5.1.x before 5.1.8 in Oracle Virtualization allows local users to affect availability via vectors related to Core, a different vulnerability than CVE-2016-5613.
Unspecified vulnerability in the Oracle VM VirtualBox component before 5.0.28 and 5.1.x before 5.1.8 in Oracle Virtualization allows local users to affect confidentiality, integrity, and availability via vectors related to Core.
Unspecified vulnerability in the Oracle VM VirtualBox component before 5.0.28 and 5.1.x before 5.1.8 in Oracle Virtualization allows local users to affect confidentiality via vectors related to Core.
Unspecified vulnerability in the Oracle VM VirtualBox component before 5.0.28 and 5.1.x before 5.1.8 in Oracle Virtualization allows local users to affect availability via vectors related to Core, a different vulnerability than CVE-2016-5608.
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle VM VirtualBox. CVSS 3.0 Base Score 6.5 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H).
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized ability to cause a partial denial of service (partial DOS) of Oracle VM VirtualBox. CVSS 3.0 Base Score 2.8 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L).
Vulnerability in the Oracle VM VirtualBox component of Oracle Virtualization (subcomponent: Core). Supported versions that are affected are Prior to 5.2.32 and prior to 6.0.10. Easily exploitable vulnerability allows low privileged attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox. While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products. Successful attacks of this vulnerability can result in unauthorized access to critical data or complete access to all Oracle VM VirtualBox accessible data. CVSS 3.0 Base Score 6.5 (Confidentiality impacts). CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N).
It was found that a guest can DoS a host by triggering an infinite loop in microcode. If a guest in 32-bit mode enabled alignment exceptions, puts the exception handler in ring 3, and then triggers an alignment exception with an unaligned stack, then the microcode will enter an infinite loop. Because there's no instruction boundary the core never receives another interrupt (including SMIs). The host kernel panics pretty quickly due to the effects.
A privileged user inside guest could use this flaw to crash the host kernel resulting in DoS.
Upstream KVM patch: ------------------- -> http://permalink.gmane.org/gmane.linux.kernel/2082329
References: ----------- -> http://www.openwall.com/lists/oss-security/2015/11/10/1
Unspecified vulnerability in the Oracle VM VirtualBox component in Oracle Virtualization VirtualBox before 4.0.34, 4.1.42, 4.2.34, 4.3.32, and 5.0.8, when a VM has the Remote Display feature (RDP) enabled, allows remote attackers to affect availability via unknown vectors related to Core.
Unspecified vulnerability in the Oracle VM VirtualBox component in Oracle Virtualization VirtualBox prior to 4.0.34, 4.1.42, 4.2.34, 4.3.32, and 5.0.8, when using a Windows guest, allows local users to affect availability via unknown vectors related to Core.
A memory leak vulnerability was found in the way OpenSSL parsed PKCS#7 and CMS data. A remote attacker could use this flaw to cause an application that parses PKCS#7 or CMS data from untrusted sources to use an excessive amount of memory and possibly crash.
ssl/s3clnt.c in OpenSSL 1.0.0 before 1.0.0t, 1.0.1 before 1.0.1p, and 1.0.2 before 1.0.2d, when used for a multi-threaded client, writes the PSK identity hint to an incorrect data structure, which allows remote servers to cause a denial of service (race condition and double free) via a crafted ServerKeyExchange message.
Unspecified vulnerability in the Oracle VM VirtualBox component in Oracle Virtualization VirtualBox before 4.3.36 and 5.0.14 allows remote attackers to affect availability via unknown vectors related to Core.
Unspecified vulnerability in the Oracle VM VirtualBox component in Oracle Virtualization VirtualBox before 4.3.36 and before 5.0.14 allows local users to affect availability via unknown vectors related to Core.