ID CVE-2015-2152
Summary Xen 4.5.x and earlier enables certain default backends when emulating a VGA device for an x86 HVM guest qemu even when the configuration disables them, which allows local guest users to obtain access to the VGA console by (1) setting the DISPLAY environment variable, when compiled with SDL support, or connecting to the VNC server on (2) ::1 or (3) 127.0.0.1, when not compiled with SDL support.
References
Vulnerable Configurations
  • Xen Xen 4.5.0
    cpe:2.3:o:xen:xen:4.5.0
  • Fedora 20
    cpe:2.3:o:fedoraproject:fedora:20
  • Fedora 21
    cpe:2.3:o:fedoraproject:fedora:21
  • Fedora 22
    cpe:2.3:o:fedoraproject:fedora:22
CVSS
Base: 1.9 (as of 23-08-2016 - 14:36)
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.
Access
VectorComplexityAuthentication
LOCAL MEDIUM NONE
Impact
ConfidentialityIntegrityAvailability
NONE PARTIAL NONE
nessus via4
  • NASL family OracleVM Local Security Checks
    NASL id ORACLEVM_OVMSA-2015-0096.NASL
    description The remote OracleVM system is missing necessary patches to address critical security updates : please see Oracle VM Security Advisory OVMSA-2015-0096 for details.
    last seen 2019-02-21
    modified 2018-07-24
    plugin id 85038
    published 2015-07-28
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=85038
    title OracleVM 3.2 : xen (OVMSA-2015-0096)
  • NASL family FreeBSD Local Security Checks
    NASL id FREEBSD_PKG_0D732FD127E011E5A4A5002590263BF5.NASL
    description The Xen Project reports : When instantiating an emulated VGA device for an x86 HVM guest qemu will by default enable a backend to expose that device, either SDL or VNC depending on the version of qemu and the build time configuration. The libxl toolstack library does not explicitly disable these default backends when they are not enabled, leading to an unexpected backend running. If either SDL or VNC is explicitly enabled in the guest configuration then only the expected backends will be enabled. This affects qemu-xen and qemu-xen-traditional differently. If qemu-xen was compiled with SDL support then this would result in an SDL window being opened if $DISPLAY is valid, or a failure to start the guest if not. If qemu-xen was compiled without SDL support then qemu would instead start a VNC server listening on ::1 (IPv6 localhost) or 127.0.0.1 (IPv4 localhost) with IPv6 preferred if available. A VNC password will not be configured even if one is present in the guest configuration. qemu-xen-traditional will never start a vnc backend unless explicitly configured. However by default it will start an SDL backend if it was built with SDL support and $DISPLAY is valid.
    last seen 2019-02-21
    modified 2018-11-10
    plugin id 84693
    published 2015-07-14
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=84693
    title FreeBSD : xen-tools -- HVM qemu unexpectedly enabling emulated VGA graphics backends (0d732fd1-27e0-11e5-a4a5-002590263bf5)
  • NASL family SuSE Local Security Checks
    NASL id SUSE_SU-2015-0613-1.NASL
    description The XEN hypervisor received updates to fix various security issues and bugs. The following security issues were fixed : - CVE-2015-2151: XSA-123: A hypervisor memory corruption due to x86 emulator flaw. - CVE-2015-2045: XSA-122: Information leak through version information hypercall. - CVE-2015-2044: XSA-121: Information leak via internal x86 system device emulation. - CVE-2015-2152: XSA-119: HVM qemu was unexpectedly enabling emulated VGA graphics backends. - CVE-2014-3615: Information leakage when guest sets high graphics resolution. - CVE-2015-0361: XSA-116: A xen crash due to use after free on hvm guest teardown. - CVE-2014-9065, CVE-2014-9066: XSA-114: xen: p2m lock starvation. Also the following bugs were fixed : - bnc#919098 - XEN blktap device intermittently fails to connect - bnc#882089 - Windows 2012 R2 fails to boot up with greater than 60 vcpus - bnc#903680 - Problems with detecting free loop devices on Xen guest startup - bnc#861318 - xentop reports 'Found interface vif101.0 but domain 101 does not exist.' - Update seabios to rel-1.7.3.1 which is the correct version for Xen 4.4 - Enhancement to virsh/libvirtd 'send-key' command The xen side small fix. (FATE#317240) - bnc#901488 - Intel ixgbe driver assigns rx/tx queues per core resulting in irq problems on servers with a large amount of CPU cores - bnc#910254 - SLES11 SP3 Xen VT-d igb NIC doesn't work - Add domain_migrate_constraints_set API to Xend's http interface (FATE#317239) - Restore missing fixes from block-dmmd script - bnc#904255 - XEN boot hangs in early boot on UEFI system - bsc#912011 - high ping latency after upgrade to latest SLES11SP3 on xen Dom0 - Fix missing banner by restoring the figlet program. 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 2018-11-29
    plugin id 83707
    published 2015-05-20
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=83707
    title SUSE SLED12 / SLES12 Security Update : Xen (SUSE-SU-2015:0613-1)
  • NASL family OracleVM Local Security Checks
    NASL id ORACLEVM_OVMSA-2018-0248.NASL
    description The remote OracleVM system is missing necessary patches to address critical security updates : please see Oracle VM Security Advisory OVMSA-2018-0248 for details.
    last seen 2019-02-21
    modified 2018-11-19
    plugin id 111992
    published 2018-08-20
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=111992
    title OracleVM 3.4 : xen (OVMSA-2018-0248) (Bunker Buster) (Foreshadow) (Meltdown) (POODLE) (Spectre)
  • NASL family Gentoo Local Security Checks
    NASL id GENTOO_GLSA-201504-04.NASL
    description The remote host is affected by the vulnerability described in GLSA-201504-04 (Xen: Multiple vulnerabilities) Multiple vulnerabilities have been discovered in Xen. Please review the CVE identifiers referenced below for details. Impact : A local attacker could possibly cause a Denial of Service condition or obtain sensitive information. Workaround : There is no known workaround at this time.
    last seen 2019-02-21
    modified 2015-04-17
    plugin id 82734
    published 2015-04-13
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=82734
    title GLSA-201504-04 : Xen: Multiple vulnerabilities
  • NASL family SuSE Local Security Checks
    NASL id OPENSUSE-2015-434.NASL
    description Xen was updated to 4.4.2 to fix multiple vulnerabilities and non-security bugs. The following vulnerabilities were fixed : - CVE-2015-4103: Potential unintended writes to host MSI message data field via qemu (XSA-128) (boo#931625) - CVE-2015-4104: PCI MSI mask bits inadvertently exposed to guests (XSA-129) (boo#931626) - CVE-2015-4105: Guest triggerable qemu MSI-X pass-through error messages (XSA-130) (boo#931627) - CVE-2015-4106: Unmediated PCI register access in qemu (XSA-131) (boo#931628) - CVE-2015-4164: DoS through iret hypercall handler (XSA-136) (boo#932996) - CVE-2015-4163: GNTTABOP_swap_grant_ref operation misbehavior (XSA-134) (boo#932790) - CVE-2015-3209: heap overflow in qemu pcnet controller allowing guest to host escape (XSA-135) (boo#932770) - CVE-2015-3456: Fixed a buffer overflow in the floppy drive emulation, which could be used to denial of service attacks or potential code execution against the host. () - CVE-2015-3340: Xen did not initialize certain fields, which allowed certain remote service domains to obtain sensitive information from memory via a (1) XEN_DOMCTL_gettscinfo or (2) XEN_SYSCTL_getdomaininfolist request. () - CVE-2015-2752: Long latency MMIO mapping operations are not preemptible (XSA-125 boo#922705) - CVE-2015-2756: Unmediated PCI command register access in qemu (XSA-126 boo#922706) - CVE-2015-2751: Certain domctl operations may be abused to lock up the host (XSA-127 boo#922709) - CVE-2015-2151: Hypervisor memory corruption due to x86 emulator flaw (boo#919464 XSA-123) - CVE-2015-2045: Information leak through version information hypercall (boo#918998 XSA-122) - CVE-2015-2044: Information leak via internal x86 system device emulation (boo#918995 (XSA-121) - CVE-2015-2152: HVM qemu unexpectedly enabling emulated VGA graphics backends (boo#919663 XSA-119) - CVE-2014-3615: information leakage when guest sets high resolution (boo#895528) The following non-security bugs were fixed : - xentop: Fix memory leak on read failure - boo#923758: xen dmesg contains bogus output in early boot - boo#921842: Xentop doesn't display disk statistics for VMs using qdisks - boo#919098: L3: XEN blktap device intermittently fails to connect - boo#882089: Windows 2012 R2 fails to boot up with greater than 60 vcpus - boo#903680: Problems with detecting free loop devices on Xen guest startup - boo#861318: xentop reports 'Found interface vif101.0 but domain 101 does not exist.' - boo#901488: Intel ixgbe driver assigns rx/tx queues per core resulting in irq problems on servers with a large amount of CPU cores - boo#910254: SLES11 SP3 Xen VT-d igb NIC doesn't work - boo#912011: high ping latency after upgrade to latest SLES11SP3 on xen Dom0 - boo#906689: let systemd schedule xencommons after network-online.target and remote-fs.target so that xendomains has access to remote shares The following functionality was enabled or enhanced : - Enable spice support in qemu for x86_64 - Add Qxl vga support - Enhancement to virsh/libvirtd 'send-key' command (FATE#317240) - Add domain_migrate_constraints_set API to Xend's http interface (FATE#317239)
    last seen 2019-02-21
    modified 2015-10-22
    plugin id 84333
    published 2015-06-23
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=84333
    title openSUSE Security Update : xen (openSUSE-2015-434) (Venom)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2015-3721.NASL
    description HVM qemu unexpectedly enabling emulated VGA graphics backends [XSA-119, CVE-2015-2152] Hypervisor memory corruption due to x86 emulator flaw [XSA-123, CVE-2015-2151] Information leak via internal x86 system device emulation, Information leak through version information hypercall Note that Tenable Network Security has extracted the preceding description block directly from the Fedora 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 2015-10-19
    plugin id 82051
    published 2015-03-25
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=82051
    title Fedora 20 : xen-4.3.3-12.fc20 (2015-3721)
  • NASL family OracleVM Local Security Checks
    NASL id ORACLEVM_OVMSA-2015-0095.NASL
    description The remote OracleVM system is missing necessary patches to address critical security updates : - ide: Clear DRQ after handling all expected accesses This is additional hardening against an end_transfer_func that fails to clear the DRQ status bit. The bit must be unset as soon as the PIO transfer has completed, so it's better to do this in a central place instead of duplicating the code in all commands (and forgetting it in some). This is XSA-138 CVE-2015-5154 (CVE-2015-5154) - ide/atapi: Fix START STOP UNIT command completion The command must be completed on all code paths. START STOP UNIT with pwrcnd set should succeed without doing anything. This is XSA-138 CVE-2015-5154 (CVE-2015-5154) - ide: Check array bounds before writing to io_buffer (CVE-2015-5154) If the end_transfer_func of a command is called because enough data has been read or written for the current PIO transfer, and it fails to correctly call the command completion functions, the DRQ bit in the status register and s->end_transfer_func may remain set. This allows the guest to access further bytes in s->io_buffer beyond s->data_end, and eventually overflowing the io_buffer. One case where this currently happens is emulation of the ATAPI command START STOP UNIT. This patch fixes the problem by adding explicit array bounds checks before accessing the buffer instead of relying on end_transfer_func to function correctly. Cc : This is XSA-138 (CVE-2015-5154) - ide: Clear DRQ after handling all expected accesses This is additional hardening against an end_transfer_func that fails to clear the DRQ status bit. The bit must be unset as soon as the PIO transfer has completed, so it's better to do this in a central place instead of duplicating the code in all commands (and forgetting it in some). This is XSA-138 (CVE-2015-5154) - ide: Check array bounds before writing to io_buffer If the end_transfer_func of a command is called because enough data has been read or written for the current PIO transfer, and it fails to correctly call the command completion functions, the DRQ bit in the status register and s->end_transfer_func may remain set. This allows the guest to access further bytes in s->io_buffer beyond s->data_end, and eventually overflowing the io_buffer. One case where this currently happens is emulation of the ATAPI command START STOP UNIT. This patch fixes the problem by adding explicit array bounds checks before accessing the buffer instead of relying on end_transfer_func to function correctly. Cc : This is XSA-138 (CVE-2015-5154) - tools: libxl: Explicitly disable graphics backends on qemu cmdline By default qemu will try to create some sort of backend for the emulated VGA device, either SDL or VNC. However when the user specifies sdl=0 and vnc=0 in their configuration libxl was not explicitly disabling either backend, which could lead to one unexpectedly running. If either sdl=1 or vnc=1 is configured then both before and after this change only the backends which are explicitly enabled are configured, i.e. this issue only occurs when all backends are supposed to have been disabled. This affects qemu-xen and qemu-xen-traditional differently. If qemu-xen was compiled with SDL support then this would result in an SDL window being opened if $DISPLAY is valid, or a failure to start the guest if not. Passing '-display none' to qemu before any further -sdl options disables this default behaviour and ensures that SDL is only started if the libxl configuration demands it. If qemu-xen was compiled without SDL support then qemu would instead start a VNC server listening on ::1 (IPv6 localhost) or 127.0.0.1 (IPv4 localhost) with IPv6 preferred if available. Explicitly pass '-vnc none' when vnc is not enabled in the libxl configuration to remove this possibility. qemu-xen-traditional would never start a vnc backend unless asked. However by default it will start an SDL backend, the way to disable this is to pass a -vnc option. In other words passing '-vnc none' will disable both vnc and sdl by default. sdl can then be reenabled if configured by subsequent use of the -sdl option. Tested with both qemu-xen and qemu-xen-traditional built with SDL support and: xl cr # defaults xl cr sdl=0 vnc=0 xl cr sdl=1 vnc=0 xl cr sdl=0 vnc=1 xl cr sdl=0 vnc=0 vga='none' xl cr sdl=0 vnc=0 nographic=1 with both valid and invalid $DISPLAY. This is XSA-119 / CVE-2015-2152. (CVE-2015-2152)
    last seen 2019-02-21
    modified 2018-07-24
    plugin id 85037
    published 2015-07-28
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=85037
    title OracleVM 3.3 : xen (OVMSA-2015-0095)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2015-3944.NASL
    description Additional patch for XSA-98 on arm64 HVM qemu unexpectedly enabling emulated VGA graphics backends [XSA-119, CVE-2015-2152] Hypervisor memory corruption due to x86 emulator flaw [XSA-123, CVE-2015-2151] enable building pngs from fig files which is working again, fix oxenstored.service preset preuninstall script, arm: vgic: incorrect rate limiting of guest triggered logging, Information leak via internal x86 system device emulation, Information leak through version information hypercall Note that Tenable Network Security has extracted the preceding description block directly from the Fedora 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 2015-10-19
    plugin id 82054
    published 2015-03-25
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=82054
    title Fedora 21 : xen-4.4.1-16.fc21 (2015-3944)
  • NASL family SuSE Local Security Checks
    NASL id OPENSUSE-2015-314.NASL
    description Xen was updated to 4.3.4 to fix multiple vulnerabities and non-security bugs. The following vulnerabilities were fixed : - Long latency MMIO mapping operations are not preemptible (XSA-125 CVE-2015-2752 bnc#922705) - Unmediated PCI command register access in qemu (XSA-126 CVE-2015-2756 bnc#922706) - Hypervisor memory corruption due to x86 emulator flaw (bnc#919464 CVE-2015-2151 XSA-123) - Information leak through version information hypercall (bnc#918998 CVE-2015-2045 XSA-122) - Information leak via internal x86 system device emulation (bnc#918995 (CVE-2015-2044 XSA-121) - HVM qemu unexpectedly enabling emulated VGA graphics backends (bnc#919663 CVE-2015-2152 XSA-119) - information leakage when guest sets high resolution (bnc#895528 CVE-2014-3615) The following non-security bugs were fixed : - L3: XEN blktap device intermittently fails to connect (bnc#919098) - Problems with detecting free loop devices on Xen guest startup (bnc#903680) - xentop reports 'Found interface vif101.0 but domain 101 does not exist.' (bnc#861318) - Intel ixgbe driver assigns rx/tx queues per core resulting in irq problems on servers with a large amount of CPU cores (bnc#901488) - SLES11 SP3 Xen VT-d igb NIC doesn't work (bnc#910254)
    last seen 2019-02-21
    modified 2015-04-21
    plugin id 82907
    published 2015-04-21
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=82907
    title openSUSE Security Update : xen (openSUSE-2015-314)
  • NASL family Fedora Local Security Checks
    NASL id FEDORA_2015-3935.NASL
    description Additional patch for XSA-98 on arm64 HVM qemu unexpectedly enabling emulated VGA graphics backends [XSA-119, CVE-2015-2152] Hypervisor memory corruption due to x86 emulator flaw [XSA-123, CVE-2015-2151] Information leak via internal x86 system device emulation, Information leak through version information hypercall, fix a typo in xen.fedora.systemd.patch Note that Tenable Network Security has extracted the preceding description block directly from the Fedora 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 2015-10-19
    plugin id 81987
    published 2015-03-23
    reporter Tenable
    source https://www.tenable.com/plugins/index.php?view=single&id=81987
    title Fedora 22 : xen-4.5.0-6.fc22 (2015-3935)
refmap via4
bid 73068
confirm http://xenbits.xen.org/xsa/advisory-119.html
fedora
  • FEDORA-2015-3721
  • FEDORA-2015-3935
  • FEDORA-2015-3944
gentoo GLSA-201504-04
sectrack
  • 1031806
  • 1031919
suse openSUSE-SU-2015:0732
Last major update 02-01-2017 - 21:59
Published 18-03-2015 - 12:59
Last modified 30-10-2018 - 12:26
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