ID CVE-2018-15468
Summary An issue was discovered in Xen through 4.11.x. The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service.
References
Vulnerable Configurations
  • Xen 4.11.0
    cpe:2.3:o:xen:xen:4.11.0
CVSS
Base: 4.9
Impact:
Exploitability:
CWE CWE-264
CAPEC
  • Accessing, Modifying or Executing Executable Files
    An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
  • Leverage Executable Code in Non-Executable Files
    An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/) http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
  • Blue Boxing
    This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
  • Target Programs with Elevated Privileges
    This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
nessus via4
  • NASL family Misc.
    NASL id XEN_SERVER_XSA-269.NASL
    description According to its self-reported version number, the Xen hypervisor installed on the remote host is affected by a denial of service vulnerability. Note that Nessus has checked the changeset versions based on the xen.git change log. Nessus did not check guest hardware configurations or if patches were applied manually to the source code before a recompile and reinstall.
    last seen 2019-02-21
    modified 2018-12-07
    plugin id 112157
    published 2018-08-28
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=112157
    title Xen Project MSR_DEBUGCTL 'Branch Trace Store' DoS (XSA-269)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2018-3332-1.NASL
    description This update for xen fixes the following issues : CVE-2018-17963: qemu_deliver_packet_iov accepted packet sizes greater than INT_MAX, which allows attackers to cause a denial of service or possibly have unspecified other impact. (bsc#1111014) CVE-2018-15468: The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) could have locked up the entire host, causing a Denial of Service. (XSA-269) (bsc#1103276) Non security issues fixed: Kernel oops in fs/dcache.c called by d_materialise_unique() (bsc#1094508) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-12-01
    plugin id 118351
    published 2018-10-24
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=118351
    title SUSE SLES12 Security Update : xen (SUSE-SU-2018:3332-1)
  • NASL family SuSE Local Security Checks
    NASL id OPENSUSE-2018-1624.NASL
    description This update for xen fixes the following issues : Update to Xen 4.10.2 bug fix release (bsc#1027519). Security vulnerabilities fixed : - CVE-2018-19961, CVE-2018-19962: Fixed an issue related to insufficient TLB flushing with AMD IOMMUs, which potentially allowed a guest to escalate its privileges, may cause a Denial of Service (DoS) affecting the entire host, or may be able to access data it is not supposed to access. (XSA-275) (bsc#1115040) - CVE-2018-19965: Fixed an issue related to the INVPCID instruction in case non-canonical addresses are accessed, which may allow a guest to cause Xen to crash, resulting in a Denial of Service (DoS) affecting the entire host. (XSA-279) (bsc#1115045) - CVE-2018-19966: Fixed an issue related to a previous fix for XSA-240, which conflicted with shadow paging and allowed a guest to cause Xen to crash, resulting in a Denial of Service (DoS). (XSA-280) (bsc#1115047) - CVE-2018-18883: Fixed an issue related to inproper restriction of nested VT-x, which allowed a guest to cause Xen to crash, resulting in a Denial of Service (DoS). (XSA-278) (bsc#1114405) - CVE-2018-15468: Fixed incorrect MSR_DEBUGCTL handling, which allowed guests to enable Branch Trace Store and may cause a Denial of Service (DoS) of the entire host. (XSA-269) (bsc#1103276) - CVE-2018-15469: Fixed use of v2 grant tables on ARM, which were not properly implemented and may cause a Denial of Service (DoS). (XSA-268) (bsc#1103275) - CVE-2018-15470: Fixed an issue in the logic in oxenstored for handling writes, which allowed a guest to write memory unbounded leading to system-wide Denial of Service (DoS). (XSA-272) (bsc#1103279) - CVE-2018-3646: Mitigations for VMM aspects of L1 Terminal Fault (XSA-273) (bsc#1091107) Other bugs fixed : - Fixed an issue related to a domU hang on SLE12-SP3 HV (bsc#1108940) - Fixed an issue with xpti=no-dom0 not working as expected (bsc#1105528) - Fixed a kernel oops related to fs/dcache.c called by d_materialise_unique() (bsc#1094508) This update was imported from the SUSE:SLE-15:Update update project.
    last seen 2019-02-21
    modified 2018-12-31
    plugin id 119951
    published 2018-12-31
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=119951
    title openSUSE Security Update : xen (openSUSE-2018-1624) (Foreshadow)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2018-4300-1.NASL
    description This update for xen fixes the following issues : Update to Xen 4.10.2 bug fix release (bsc#1027519). Security vulnerabilities fixed : CVE-2018-19961, CVE-2018-19962: Fixed an issue related to insufficient TLB flushing with AMD IOMMUs, which potentially allowed a guest to escalate its privileges, may cause a Denial of Service (DoS) affecting the entire host, or may be able to access data it is not supposed to access. (XSA-275) (bsc#1115040) CVE-2018-19965: Fixed an issue related to the INVPCID instruction in case non-canonical addresses are accessed, which may allow a guest to cause Xen to crash, resulting in a Denial of Service (DoS) affecting the entire host. (XSA-279) (bsc#1115045) CVE-2018-19966: Fixed an issue related to a previous fix for XSA-240, which conflicted with shadow paging and allowed a guest to cause Xen to crash, resulting in a Denial of Service (DoS). (XSA-280) (bsc#1115047) CVE-2018-18883: Fixed an issue related to inproper restriction of nested VT-x, which allowed a guest to cause Xen to crash, resulting in a Denial of Service (DoS). (XSA-278) (bsc#1114405) CVE-2018-15468: Fixed incorrect MSR_DEBUGCTL handling, which allowed guests to enable Branch Trace Store and may cause a Denial of Service (DoS) of the entire host. (XSA-269) (bsc#1103276) CVE-2018-15469: Fixed use of v2 grant tables on ARM, which were not properly implemented and may cause a Denial of Service (DoS). (XSA-268) (bsc#1103275) CVE-2018-15470: Fixed an issue in the logic in oxenstored for handling writes, which allowed a guest to write memory unbounded leading to system-wide Denial of Service (DoS). (XSA-272) (bsc#1103279) CVE-2018-3646: Mitigations for VMM aspects of L1 Terminal Fault (XSA-273) (bsc#1091107) Other bugs fixed: Fixed an issue related to a domU hang on SLE12-SP3 HV (bsc#1108940) Fixed an issue with xpti=no-dom0 not working as expected (bsc#1105528) Fixed a kernel oops related to fs/dcache.c called by d_materialise_unique() (bsc#1094508) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2019-01-02
    plugin id 120196
    published 2019-01-02
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=120196
    title SUSE SLED15 / SLES15 Security Update : xen (SUSE-SU-2018:4300-1) (Foreshadow)
  • NASL family SuSE Local Security Checks
    NASL id OPENSUSE-2018-1331.NASL
    description This update for xen fixes the following issues : XEN was updated to the Xen 4.9.3 bug fix only release (bsc#1027519) - CVE-2018-17963: qemu_deliver_packet_iov accepted packet sizes greater than INT_MAX, which allows attackers to cause a denial of service or possibly have unspecified other impact. (bsc#1111014) - CVE-2018-15470: oxenstored might not have enforced the configured quota-maxentity. This allowed a malicious or buggy guest to write as many xenstore entries as it wishes, causing unbounded memory usage in oxenstored. This can lead to a system-wide DoS. (XSA-272) (bsc#1103279) - CVE-2018-15469: ARM never properly implemented grant table v2, either in the hypervisor or in Linux. Unfortunately, an ARM guest can still request v2 grant tables; they will simply not be properly set up, resulting in subsequent grant-related hypercalls hitting BUG() checks. An unprivileged guest can cause a BUG() check in the hypervisor, resulting in a denial-of-service (crash). (XSA-268) (bsc#1103275) Note that SUSE does not ship ARM Xen, so we are not affected. - CVE-2018-15468: The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service. (XSA-269) (bsc#1103276) - CVE-2018-3646: Systems with microprocessors utilizing speculative execution and address translations may have allowed unauthorized disclosure of information residing in the L1 data cache to an attacker with local user access with guest OS privilege via a terminal page fault and a side-channel analysis. (XSA-273) (bsc#1091107) Non security issues fixed : - The affinity reporting via 'xl vcpu-list' was broken (bsc#1106263) - Kernel oops in fs/dcache.c called by d_materialise_unique() (bsc#1094508) This update was imported from the SUSE:SLE-12-SP3:Update update project.
    last seen 2019-02-21
    modified 2018-11-26
    plugin id 118563
    published 2018-10-31
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=118563
    title openSUSE Security Update : xen (openSUSE-2018-1331) (Foreshadow)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2018-3490-1.NASL
    description This update for xen fixes the following issues : XEN was updated to the Xen 4.9.3 bug fix only release (bsc#1027519) CVE-2018-17963: qemu_deliver_packet_iov accepted packet sizes greater than INT_MAX, which allows attackers to cause a denial of service or possibly have unspecified other impact. (bsc#1111014) CVE-2018-15470: oxenstored might not have enforced the configured quota-maxentity. This allowed a malicious or buggy guest to write as many xenstore entries as it wishes, causing unbounded memory usage in oxenstored. This can lead to a system-wide DoS. (XSA-272) (bsc#1103279) CVE-2018-15469: ARM never properly implemented grant table v2, either in the hypervisor or in Linux. Unfortunately, an ARM guest can still request v2 grant tables; they will simply not be properly set up, resulting in subsequent grant-related hypercalls hitting BUG() checks. An unprivileged guest can cause a BUG() check in the hypervisor, resulting in a denial-of-service (crash). (XSA-268) (bsc#1103275) Note that SUSE does not ship ARM Xen, so we are not affected. CVE-2018-15468: The DEBUGCTL MSR contains several debugging features, some of which virtualise cleanly, but some do not. In particular, Branch Trace Store is not virtualised by the processor, and software has to be careful to configure it suitably not to lock up the core. As a result, it must only be available to fully trusted guests. Unfortunately, in the case that vPMU is disabled, all value checking was skipped, allowing the guest to choose any MSR_DEBUGCTL setting it likes. A malicious or buggy guest administrator (on Intel x86 HVM or PVH) can lock up the entire host, causing a Denial of Service. (XSA-269) (bsc#1103276) CVE-2018-3646: Systems with microprocessors utilizing speculative execution and address translations may have allowed unauthorized disclosure of information residing in the L1 data cache to an attacker with local user access with guest OS privilege via a terminal page fault and a side-channel analysis. (XSA-273) (bsc#1091107) Non security issues fixed: The affinity reporting via 'xl vcpu-list' was broken (bsc#1106263) Kernel oops in fs/dcache.c called by d_materialise_unique() (bsc#1094508) Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-12-01
    plugin id 118491
    published 2018-10-29
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=118491
    title SUSE SLED12 / SLES12 Security Update : xen (SUSE-SU-2018:3490-1) (Foreshadow)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-915602DF63.NASL
    description L1 Terminal Fault speculative side channel patch bundle [XSA-273, CVE-2018-3620, CVE-2018-3646] drop patches also in the bundle, which also includes Use of v2 grant tables may cause crash on ARM [XSA-268] (#1616081) x86: Incorrect MSR_DEBUGCTL handling lets guests enable BTS [XSA-269] (#1616077) oxenstored does not apply quota-maxentity [XSA-272] (#1616080) Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2018-11-02
    plugin id 112234
    published 2018-09-04
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=112234
    title Fedora 27 : xen (2018-915602df63) (Foreshadow)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2018-683DFDE81A.NASL
    description L1 Terminal Fault speculative side channel patch bundle [XSA-273, CVE-2018-3620, CVE-2018-3646] drop patches also in the bundle, which also includes Use of v2 grant tables may cause crash on ARM [XSA-268] (#1616081) x86: Incorrect MSR_DEBUGCTL handling lets guests enable BTS [XSA-269] (#1616077) oxenstored does not apply quota-maxentity [XSA-272] (#1616080) Note that Tenable Network Security has extracted the preceding description block directly from the Fedora update system website. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2019-02-21
    modified 2019-01-03
    plugin id 120490
    published 2019-01-03
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=120490
    title Fedora 28 : xen (2018-683dfde81a) (Foreshadow)
  • NASL family Gentoo Local Security Checks
    NASL id GENTOO_GLSA-201810-06.NASL
    description The remote host is affected by the vulnerability described in GLSA-201810-06 (Xen: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in Xen. Please review the referenced CVE identifiers for details. Impact : A local attacker could cause a Denial of Service condition or disclose sensitive information. Workaround : There is no known workaround at this time.
    last seen 2019-02-21
    modified 2018-10-31
    plugin id 118506
    published 2018-10-31
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=118506
    title GLSA-201810-06 : Xen: Multiple vulnerabilities (Foreshadow) (Meltdown) (Spectre)
  • NASL family OracleVM Local Security Checks
    NASL id ORACLEVM_OVMSA-2018-0282.NASL
    description The remote OracleVM system is missing necessary patches to address critical security updates : please see Oracle VM Security Advisory OVMSA-2018-0282 for details.
    last seen 2019-02-21
    modified 2018-11-29
    plugin id 119277
    published 2018-11-29
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=119277
    title OracleVM 3.4 : xen (OVMSA-2018-0282) (Foreshadow) (Spectre)
refmap via4
gentoo GLSA-201810-06
misc http://xenbits.xen.org/xsa/advisory-269.html
Last major update 17-08-2018 - 14:29
Published 17-08-2018 - 14:29
Last modified 01-11-2018 - 10:21
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