Detections
Analytics
Citrix XenServer Multiple Vulnerabilities (CTX218775)
high Nessus Plugin ID 95539
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Synopsis
The remote host is affected by multiple vulnerabilities.Description
The version of Citrix XenServer running on the remote host is missing a security hotfix. It is, therefore, affected by multiple vulnerabilities :- A flaw exists in the sniff_netware() function within file tools/pygrub/src/pygrub when handling string quotes and S-expressions in the bootloader whenever the S-expressions output format is requested. A guest attacker can exploit this to cause the bootloader configuration file to produce incorrect output, resulting in the disclosure or deletion of files from the host. (CVE-2016-9379)
- A flaw exists in the sniff_netware() function within file tools/pygrub/src/pygrub when handling NULL bytes in the bootloader whenever the null-delimited output format is requested. A guest attacker can exploit this to cause configuration files to output ambiguous or confusing results, resulting in the disclosure or deletion of files from the host. (CVE-2016-9380)
- A double-fetch flaw exists that is triggered when the compiler omits QEMU optimizations. A guest attacker can exploit this to gain elevated privileges on the host.
(CVE-2016-9381)
- A flaw exists in the hvm_task_switch() function within file arch/x86/hvm/hvm.c due to improper handling of x86 task switching to VM86 mode. A guest attacker can exploit this to cause a denial of service condition or gain elevated privileges within the guest environment.
(CVE-2016-9382)
- A flaw exists in the x86_emulate() function within file arch/x86/x86_emulate/x86_emulate.c that allows a guest attacker to cause changes to memory and thereby gain elevated privileges on the host. (CVE-2016-9383)
- A denial of service vulnerability exists in the x86 segment base write emulation that is related to lacking canonical address checks. A local attacker who has administrative rights within a guest can exploit this issue to crash the host. (CVE-2016-9385)
- A flaw exists in the x86 emulator due to improper checking of the usability of segments when performing memory accesses. A guest attacker can exploit this to gain elevated privileges. (CVE-2016-9386)
Solution
Apply the appropriate hotfix according to the vendor advisory.See Also
Plugin Details
Severity: High
ID: 95539
File Name: citrix_xenserver_CTX218775.nasl
Version: 1.8
Type: local
Family: Misc.
Published: 12/5/2016
Updated: 11/13/2019
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 6.5
CVSS v2
Risk Factor: High
Base Score: 7.2
Temporal Score: 5.3
Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2016-9383
CVSS v3
Risk Factor: High
Base Score: 8.8
Temporal Score: 7.7
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/a:citrix:xenserver
Required KB Items: Host/XenServer/version, Host/local_checks_enabled
Exploit Ease: No known exploits are available
Patch Publication Date: 11/22/2016
Vulnerability Publication Date: 11/22/2016
Reference Information
CVE: CVE-2016-9379, CVE-2016-9380, CVE-2016-9381, CVE-2016-9382, CVE-2016-9383, CVE-2016-9385, CVE-2016-9386