據發現，Cirrus blit 區域檢查不足。有權限的來賓使用者可利用此瑕疵，在主機之含有攻擊者供應資料的 QEMU 處理程序位址空間中，寫入 VRAM 配置的緩衝區邊界之外。(CVE-2014-8106)

在 set_pixel_format() 函式清理 bits_per_pixel 之值的方式中，發現一個未初始化的資料結構使用瑕疵。攻擊者若能存取來賓的 VNC 主控台，便可利用此瑕疵使來賓當機。(CVE-2014-7815)

據發現，移轉期間載入 RAM 時讀取的某些值未經過驗證。使用者若可變更 savevm 資料 (磁碟上或移轉時在線)，便可利用這些瑕疵的任何一種來損毀 (目的地) 主機上的 QEMU 處理程序記憶體，進而可能在主機上透過 QEMU 處理程序的權限執行任意程式碼。
(CVE-2014-7840)

在使用 QEMU 之使用者網路的情況下，QEMU 處理含來源連接埠且位址為 0 之 UDP 封包的方式有一個 NULL 指標解除參照瑕疵。本機來賓使用者可利用此瑕疵使來賓當機。(CVE-2014-3640)

錯誤修正：

- KVM 公用程式在每次執行 MSI 向量遮罩/取消遮罩作業時，都會執行關鍵的路由更新系統呼叫。因此，執行舊版系統 (如 Scientific Linux 5) 的來賓在某些情況下，可能有速度嚴重減慢的現象。現在會在遮罩/取消遮罩作業時忽略路由系統呼叫，且舊版來賓的效能目前較為一致。

- 由於 Internet Small Computer System Interface (iSCSI) 驅動程式中的錯誤，當‘write same’命令在 iSCSI 通訊協定的來賓模式中執行時，qemu-kvm 處理程序會因分割錯誤而意外終止。此更新可修正該錯誤，且’write same’命令現可在 iSCSI 的來賓模式中如預期運作。

- QEMU 命令介面未正確處理來賓移轉期間的快取記憶體大小重新調整，造成 QEMU 因分割錯誤而意外終止。此更新可修正相關程式碼，且 QEMU 不會再在所述情況下當機。

增強功能：

- KVM 來賓中的支援虛擬 CPU (vCPU) 數量上限已增為 240。此可增加使用者可指派給來賓的虛擬處理單位的數量，因此能改善其效能潛力。

- QEMU Hypervisor、KVM 核心程式碼和 libvirt API 已新增第 5 代 Intel Core 處理器支援。這讓 KVM 來賓得以使用以下指示和功能：ADCX、ADOX、RDSFEED、PREFETCHW 和監督模式存取防止 (SMAP)。

- ‘dump-guest-memory’ 命令現可支援當機轉儲存壓縮。這讓無法使用‘virsh dump’命令的使用者，不需太多的磁碟空間就能執行來賓當機轉儲存。此外，儲存壓縮之來賓當機轉儲存所需的時間通常少於儲存非壓縮的項目。

更新版 qemu 套件可修正多個安全性弱點：

Sibiao Luo 發現 QEMU 未正確處理裝置熱插拔的拔除。本機使用者可能利用此瑕疵造成拒絕服務 (CVE-2013-4377)。

Michael S. Tsirkin 發現，QEMU 並未正確處理 vmxnet3 裝置。本機來賓可能會利用此問題，引發拒絕服務或可能在主機上執行任意程式碼 (CVE-2013-4544)。

在各種 QEMU 區塊驅動程式中發現多個整數溢位、輸入驗證、邏輯錯誤和緩衝區溢位瑕疵。攻擊者若可修改來賓載入的磁碟映像檔，便能利用這些瑕疵使來賓當機，或損毀主機上的 QEMU 處理程序記憶體，進而以 QEMU 處理程序的權限在主機上導致任意程式碼執行 (CVE-2014-0143、CVE-2014-0144、 CVE-2014-0145、CVE-2014-0147)。

在 QEMU 的 virtio_net_handle_mac() 函式處理更新 MAC 位址表格之來賓要求的方式中發現一個緩衝區溢位瑕疵。有權限的來賓使用者可利用此瑕疵，損毀主機上的 QEMU 處理程序記憶體，進而可能導致以 QEMU 處理程序的權限在主機上執行任意程式碼 (CVE-2014-0150)。

在 QEMU 中 Parallels 區塊驅動程式的 seek_to_sector() 函式中發現一個除以零瑕疵。若攻擊者可修改來賓載入的磁碟映像檔，便可利用此瑕疵使來賓當機 (CVE-2014-0142)。

在 QEMU 的 QCOW2 區塊驅動程式中，發現一個 NULL 指標解除參照瑕疵。若攻擊者可修改來賓載入的磁碟映像檔，便可利用此瑕疵使來賓當機 (CVE-2014-0146)。

據發現，Hyper-V VHDX 影像的區塊驅動程式因為缺少邊界檢查，而未正確計算 BAT (區塊配置表) 項目。若攻擊者可修改來賓載入的磁碟映像檔，便可利用此瑕疵使來賓當機 (CVE-2014-0148)。

在 QEMU 的 IDE 裝置驅動程式處理 SMART EXECUTE OFFLINE 命令執行的方式中發現超出邊界記憶體存取瑕疵。
有權限的來賓使用者可利用此瑕疵，損毀主機上的 QEMU 處理程序記憶體，進而可能導致以 QEMU 處理程序的權限在主機上執行任意程式碼 (CVE-2014-2894)。

在 QCOW 第 1 版磁碟映像的 QEMU 區塊驅動程式中發現兩個整數溢位瑕疵。使用者若可變更來賓載入的 QEMU 磁碟映像檔，便可利用其中任何一個瑕疵，損毀主機上的 QEMU 處理程序記憶體，進而可能導致以 QEMU 處理程序的權限在主機上執行任意程式碼 (CVE-2014-0222、CVE-2014-0223)。

在 QEMU 的 vrtio、virtio-net、virtio-scsi 和 usb 驅動程式移轉後處理狀態載入的方式中發現多個緩衝區溢位、輸入驗證和超出邊界寫入瑕疵。使用者若可變更 savevm 資料 (磁碟上或移轉時在線)，便可利用其中任何一個瑕疵，損毀 (目的地) 主機上的 QEMU 處理程序記憶體，進而可能導致以 QEMU 處理程序的權限在主機執行任意程式碼 (CVE-2013-4148、CVE-2013-4151、CVE-2013-4535、CVE-2013-4536、 CVE-2013-4541、CVE-2013-4542、CVE-2013-6399、CVE-2014-0182、 CVE-2014-3461)。

在 QEMU VGA 模擬器存取高解析度顯示的框架緩衝區記憶體的方式中發現一個資訊洩漏瑕疵。有權限的來賓用者可利用此瑕疵，將來賓使用的顯示器設為高解析度，進而將主機的記憶體內容洩漏給來賓 (CVE-2014-3615)。

如果來賓傳送具有來源連接埠和來源 addr 0 的 udp 封包，則在搜尋比對和已建立的 udp 通訊端時，系統會擷取未初始化的通訊端，而其稍後會傳送至 sosendto()，其中在 so->slirp->vnetwork_mask.s_addr 存取期間，會發生 NULL 指標解除參照。只有使用 qemu 使用者網路的來賓會受到影響 (CVE-2014-3640)。

Intel Security 的進階威脅研究團隊報告，來賓提供的參數在 vmware-vga driver 的三角形函式中未經充分驗證。有權限的來賓使用者可利用此瑕疵，在主機上寫入 qemu 位址空間，從而可能會將自己的權限提升到可以使用 qemu 主機處理程序的權限 (CVE-2014-3689)。

據發現，QEMU 會不正確處理 USB xHCI 控制器的即時移轉。攻擊者可能會利用此瑕疵，引發拒絕服務或可能執行任意程式碼 (CVE-2014-5263)。

Cisco 的 James Spadaro 報告，在 QEMU VNC 顯示驅動程式的用戶端中，bits_per_pixel 未充分清理。具有來賓 VNC 主控台存取權的攻擊者可利用此瑕疵造成來賓當機 (CVE-2014-7815)。

在移轉期間載入 ram 時，從移轉資料流讀取的值並未經過驗證。特別是 host_from_stream_offset() 中的位移，以及在所述函式呼叫者中的寫入長度。
使用者若可變更 savevm 資料 (磁碟上或移轉時在線)，便可利用其中任何一個瑕疵，損毀 (目的地) 主機上的 QEMU 處理程序記憶體，進而可能在主機上透過 QEMU 處理程序的權限執行任意程式碼 (CVE-2014-7840)。

Red Hat 的 Paolo Bonzini 發現在 qemu 的 Cirrus VGA 模擬器中，blit 區域檢查不充分。有權限的來賓使用者可利用此瑕疵，在主機上寫入 qemu 位址空間，從而可能會將自己的權限提升到可以使用 qemu 主機處理程序的權限 (CVE-2014-8106)。

此更新也提供 usbredirparser 0.6 做為 qemu-1.6.2 的先決條件。

QEMU was updated to fix various bugs and security issues.

Following security issues were fixed: CVE-2014-8106: Heap-based buffer overflow in the Cirrus VGA emulator (hw/display/cirrus_vga.c) in QEMU allowed local guest users to execute arbitrary code via vectors related to blit regions.

  - CVE-2014-7840: The host_from_stream_offset function in     arch_init.c in QEMU, when loading RAM during migration,     allowed remote attackers to execute arbitrary code via a     crafted (1) offset or (2) length value in savevm data.

Also a bug was fixed where qemu-img convert could occasionaly corrupt images. (bsc#908380)

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.

From Red Hat Security Advisory 2015:0349 :

Updated qemu-kvm packages that fix multiple security issues, several bugs, and add various enhancements are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section.

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. The qemu-kvm packages provide the user-space component for running virtual machines using KVM.

It was found that the Cirrus blit region checks were insufficient. A privileged guest user could use this flaw to write outside of VRAM-allocated buffer boundaries in the host's QEMU process address space with attacker-provided data. (CVE-2014-8106)

An uninitialized data structure use flaw was found in the way the set_pixel_format() function sanitized the value of bits_per_pixel. An attacker able to access a guest's VNC console could use this flaw to crash the guest. (CVE-2014-7815)

It was found that certain values that were read when loading RAM during migration were not validated. A user able to alter the savevm data (either on the disk or over the wire during migration) could use either of these flaws to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process.
(CVE-2014-7840)

A NULL pointer dereference flaw was found in the way QEMU handled UDP packets with a source port and address of 0 when QEMU's user networking was in use. A local guest user could use this flaw to crash the guest. (CVE-2014-3640)

Red Hat would like to thank James Spadaro of Cisco for reporting CVE-2014-7815, and Xavier Mehrenberger and Stephane Duverger of Airbus for reporting CVE-2014-3640. The CVE-2014-8106 issue was found by Paolo Bonzini of Red Hat, and the CVE-2014-7840 issue was discovered by Michael S. Tsirkin of Red Hat.

Bug fixes :

* The KVM utility executed demanding routing update system calls every time it performed an MSI vector mask/unmask operation. Consequently, guests running legacy systems such as Red Hat Enterprise Linux 5 could, under certain circumstances, experience significant slowdown.
Now, the routing system calls during mask/unmask operations are skipped, and the performance of legacy guests is now more consistent.
(BZ#1098976)

* Due to a bug in the Internet Small Computer System Interface (iSCSI) driver, a qemu-kvm process terminated unexpectedly with a segmentation fault when the 'write same' command was executed in guest mode under the iSCSI protocol. This update fixes the bug, and the 'write same' command now functions in guest mode under iSCSI as intended.
(BZ#1083413)

* The QEMU command interface did not properly handle resizing of cache memory during guest migration, causing QEMU to terminate unexpectedly with a segmentation fault. This update fixes the related code, and QEMU no longer crashes in the described situation. (BZ#1066338)

Enhancements :

* The maximum number of supported virtual CPUs (vCPUs) in a KVM guest has been increased to 240. This increases the number of virtual processing units that the user can assign to the guest, and therefore improves its performance potential. (BZ#1134408)

* Support for the 5th Generation Intel Core processors has been added to the QEMU hypervisor, the KVM kernel code, and the libvirt API. This allows KVM guests to use the following instructions and features:
ADCX, ADOX, RDSFEED, PREFETCHW, and supervisor mode access prevention (SMAP). (BZ#1116117)

* The 'dump-guest-memory' command now supports crash dump compression.
This makes it possible for users who cannot use the 'virsh dump' command to require less hard disk space for guest crash dumps. In addition, saving a compressed guest crash dump frequently takes less time than saving a non-compressed one. (BZ#1157798)

* This update introduces support for flight recorder tracing, which uses SystemTap to automatically capture qemu-kvm data while the guest machine is running. For detailed instructions on how to configure and use flight recorder tracing, see the Virtualization Deployment and Administration Guide, linked to in the References section below.
(BZ#1088112)

It was found that the Cirrus blit region checks were insufficient. A privileged guest user could use this flaw to write outside of VRAM- allocated buffer boundaries in the host's QEMU process address space with attacker-provided data. (CVE-2014-8106)

An uninitialized data structure use flaw was found in the way the set_pixel_format() function sanitized the value of bits_per_pixel. An attacker able to access a guest's VNC console could use this flaw to crash the guest. (CVE-2014-7815)

It was found that certain values that were read when loading RAM during migration were not validated. A user able to alter the savevm data (either on the disk or over the wire during migration) could use either of these flaws to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process.
(CVE-2014-7840)

A NULL pointer dereference flaw was found in the way QEMU handled UDP packets with a source port and address of 0 when QEMU's user networking was in use. A local guest user could use this flaw to crash the guest. (CVE-2014-3640)

Bug fixes :

  - The KVM utility executed demanding routing update system     calls every time it performed an MSI vector mask/unmask     operation. Consequently, guests running legacy systems     such as Scientific Linux 5 could, under certain     circumstances, experience significant slowdown. Now, the     routing system calls during mask/unmask operations are     skipped, and the performance of legacy guests is now     more consistent.

  - Due to a bug in the Internet Small Computer System     Interface (iSCSI) driver, a qemu-kvm process terminated     unexpectedly with a segmentation fault when the 'write     same' command was executed in guest mode under the iSCSI     protocol. This update fixes the bug, and the 'write     same' command now functions in guest mode under iSCSI as     intended.

  - The QEMU command interface did not properly handle     resizing of cache memory during guest migration, causing     QEMU to terminate unexpectedly with a segmentation     fault. This update fixes the related code, and QEMU no     longer crashes in the described situation.

Enhancements :

  - The maximum number of supported virtual CPUs (vCPUs) in     a KVM guest has been increased to 240. This increases     the number of virtual processing units that the user can     assign to the guest, and therefore improves its     performance potential.

  - Support for the 5th Generation Intel Core processors has     been added to the QEMU hypervisor, the KVM kernel code,     and the libvirt API. This allows KVM guests to use the     following instructions and features: ADCX, ADOX,     RDSFEED, PREFETCHW, and supervisor mode access     prevention (SMAP).

  - The 'dump-guest-memory' command now supports crash dump     compression. This makes it possible for users who cannot     use the 'virsh dump' command to require less hard disk     space for guest crash dumps. In addition, saving a     compressed guest crash dump frequently takes less time     than saving a non-compressed one.

The remote Redhat Enterprise Linux 5 host has one or more packages installed that are affected by multiple vulnerabilities that have been acknowledged by the vendor but will not be patched.

  - qemu: insufficient parameter validation during ram load (CVE-2014-7840)

  - Qemu: net: buffer overflow in MIPSnet emulator (CVE-2016-4002)

  - The KVM subsystem in the Linux kernel before 3.0 does not check whether kernel addresses are specified     during allocation of memory slots for use in a guest's physical address space, which allows local users to     gain privileges or obtain sensitive information from kernel memory via a crafted application, related to     arch/x86/kvm/paging_tmpl.h and virt/kvm/kvm_main.c. (CVE-2013-1943)

Note that Nessus has not tested for these issues but has instead relied on the package manager's report that the package is installed.

Updated qemu packages fix multiple security vulnerabilities :

Sibiao Luo discovered that QEMU incorrectly handled device hot-unplugging. A local user could possibly use this flaw to cause a denial of service (CVE-2013-4377).

Michael S. Tsirkin discovered that QEMU incorrectly handled vmxnet3 devices. A local guest could possibly use this issue to cause a denial of service, or possibly execute arbitrary code on the host (CVE-2013-4544).

Multiple integer overflow, input validation, logic error, and buffer overflow flaws were discovered in various QEMU block drivers. An attacker able to modify a disk image file loaded by a guest could use these flaws to crash the guest, or corrupt QEMU process memory on the host, potentially resulting in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-0143, CVE-2014-0144, CVE-2014-0145, CVE-2014-0147).

A buffer overflow flaw was found in the way the virtio_net_handle_mac() function of QEMU processed guest requests to update the table of MAC addresses. A privileged guest user could use this flaw to corrupt QEMU process memory on the host, potentially resulting in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-0150).

A divide-by-zero flaw was found in the seek_to_sector() function of the parallels block driver in QEMU. An attacker able to modify a disk image file loaded by a guest could use this flaw to crash the guest (CVE-2014-0142).

A NULL pointer dereference flaw was found in the QCOW2 block driver in QEMU. An attacker able to modify a disk image file loaded by a guest could use this flaw to crash the guest (CVE-2014-0146).

It was found that the block driver for Hyper-V VHDX images did not correctly calculate BAT (Block Allocation Table) entries due to a missing bounds check. An attacker able to modify a disk image file loaded by a guest could use this flaw to crash the guest (CVE-2014-0148).

An out-of-bounds memory access flaw was found in the way QEMU's IDE device driver handled the execution of SMART EXECUTE OFFLINE commands.
A privileged guest user could use this flaw to corrupt QEMU process memory on the host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-2894).

Two integer overflow flaws were found in the QEMU block driver for QCOW version 1 disk images. A user able to alter the QEMU disk image files loaded by a guest could use either of these flaws to corrupt QEMU process memory on the host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-0222, CVE-2014-0223).

Multiple buffer overflow, input validation, and out-of-bounds write flaws were found in the way the virtio, virtio-net, virtio-scsi, and usb drivers of QEMU handled state loading after migration. A user able to alter the savevm data (either on the disk or over the wire during migration) could use either of these flaws to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2013-4148, CVE-2013-4151, CVE-2013-4535, CVE-2013-4536, CVE-2013-4541, CVE-2013-4542, CVE-2013-6399, CVE-2014-0182, CVE-2014-3461).

An information leak flaw was found in the way QEMU's VGA emulator accessed frame buffer memory for high resolution displays. A privileged guest user could use this flaw to leak memory contents of the host to the guest by setting the display to use a high resolution in the guest (CVE-2014-3615).

When guest sends udp packet with source port and source addr 0, uninitialized socket is picked up when looking for matching and already created udp sockets, and later passed to sosendto() where NULL pointer dereference is hit during so->slirp->vnetwork_mask.s_addr access Only guests using qemu user networking are affected (CVE-2014-3640).

The Advanced Threat Research team at Intel Security reported that guest provided parameter were insufficiently validated in rectangle functions in the vmware-vga driver. A privileged guest user could use this flaw to write into qemu address space on the host, potentially escalating their privileges to those of the qemu host process (CVE-2014-3689).

It was discovered that QEMU incorrectly handled USB xHCI controller live migration. An attacker could possibly use this issue to cause a denial of service, or possibly execute arbitrary code (CVE-2014-5263).

James Spadaro of Cisco reported insufficiently sanitized bits_per_pixel from the client in the QEMU VNC display driver. An attacker having access to the guest's VNC console could use this flaw to crash the guest (CVE-2014-7815).

During migration, the values read from migration stream during ram load are not validated. Especially offset in host_from_stream_offset() and also the length of the writes in the callers of the said function.
A user able to alter the savevm data (either on the disk or over the wire during migration) could use either of these flaws to corrupt QEMU process memory on the (destination) host, which could potentially result in arbitrary code execution on the host with the privileges of the QEMU process (CVE-2014-7840).

Paolo Bonzini of Red Hat discovered that the blit region checks were insufficient in the Cirrus VGA emulator in qemu. A privileged guest user could use this flaw to write into qemu address space on the host, potentially escalating their privileges to those of the qemu host process (CVE-2014-8106).

This update also provides usbredirparser 0.6 as a prerequisite of qemu-1.6.2

ID	名前	製品	ファミリー	公開日	更新日	深刻度
82260	Scientific Linux 安全性更新：SL7.x x86_64 上的 qemu-kvm	Nessus	Scientific Linux Local Security Checks	2015/3/26	2021/1/14	high
81944	Mandriva Linux 安全性公告：qemu (MDVSA-2015:061)	Nessus	Mandriva Local Security Checks	2015/3/19	2021/1/6	high
83686	SUSE SLED12 / SLES12 Security Update : qemu (SUSE-SU-2015:0349-1)	Nessus	SuSE Local Security Checks	2015/5/20	2021/1/6	high
81803	Oracle Linux 7 : qemu-kvm (ELSA-2015-0349)	Nessus	Oracle Linux Local Security Checks	2015/3/13	2021/1/14	high
82260	Scientific Linux Security Update : qemu-kvm on SL7.x x86_64 (20150305)	Nessus	Scientific Linux Local Security Checks	2015/3/26	2021/1/14	high
199962	RHEL 5 : kvm (Unpatched Vulnerability)	Nessus	Red Hat Local Security Checks	2024/6/3	2024/6/3	critical
81944	Mandriva Linux Security Advisory : qemu (MDVSA-2015:061)	Nessus	Mandriva Local Security Checks	2015/3/19	2021/1/6	high

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