Vulnerabilities > CVE-2017-4940 - Cross-site Scripting vulnerability in VMWare Esxi 6.0/6.5
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
LOW Integrity impact
LOW Availability impact
NONE Summary
The ESXi Host Client in VMware ESXi (6.5 before ESXi650-201712103-SG, 5.5 before ESXi600-201711103-SG and 5.5 before ESXi550-201709102-SG) contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| OS | 120 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Cross Site Scripting through Log Files An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
- Embedding Scripts in Non-Script Elements This attack is a form of Cross-Site Scripting (XSS) where malicious scripts are embedded in elements that are not expected to host scripts such as image tags (<img>), comments in XML documents (< !-CDATA->), etc. These tags may not be subject to the same input validation, output validation, and other content filtering and checking routines, so this can create an opportunity for an attacker to tunnel through the application's elements and launch a XSS attack through other elements. As with all remote attacks, it is important to differentiate the ability to launch an attack (such as probing an internal network for unpatched servers) and the ability of the remote attacker to collect and interpret the output of said attack.
- Embedding Scripts within Scripts An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute scripts. The attacker leverages this capability to execute scripts to execute his/her own script by embedding it within other scripts that the target software is likely to execute. The attacker must have the ability to inject script into script that is likely to be executed. If this is done, then the attacker can potentially launch a variety of probes and attacks against the web server's local environment, in many cases the so-called DMZ, back end resources the web server can communicate with, and other hosts. With the proliferation of intermediaries, such as Web App Firewalls, network devices, and even printers having JVMs and Web servers, there are many locales where an attacker can inject malicious scripts. Since this attack pattern defines scripts within scripts, there are likely privileges to execute said attack on the host. Of course, these attacks are not solely limited to the server side, client side scripts like Ajax and client side JavaScript can contain malicious scripts as well. In general all that is required is for there to be sufficient privileges to execute a script, but not protected against writing.
- Cross-Site Scripting in Error Pages An attacker distributes a link (or possibly some other query structure) with a request to a third party web server that is malformed and also contains a block of exploit code in order to have the exploit become live code in the resulting error page. When the third party web server receives the crafted request and notes the error it then creates an error message that echoes the malformed message, including the exploit. Doing this converts the exploit portion of the message into to valid language elements that are executed by the viewing browser. When a victim executes the query provided by the attacker the infected error message error message is returned including the exploit code which then runs in the victim's browser. XSS can result in execution of code as well as data leakage (e.g. session cookies can be sent to the attacker). This type of attack is especially dangerous since the exploit appears to come from the third party web server, who the victim may trust and hence be more vulnerable to deception.
- Cross-Site Scripting Using Alternate Syntax The attacker uses alternate forms of keywords or commands that result in the same action as the primary form but which may not be caught by filters. For example, many keywords are processed in a case insensitive manner. If the site's web filtering algorithm does not convert all tags into a consistent case before the comparison with forbidden keywords it is possible to bypass filters (e.g., incomplete black lists) by using an alternate case structure. For example, the "script" tag using the alternate forms of "Script" or "ScRiPt" may bypass filters where "script" is the only form tested. Other variants using different syntax representations are also possible as well as using pollution meta-characters or entities that are eventually ignored by the rendering engine. The attack can result in the execution of otherwise prohibited functionality.
Nessus
NASL family VMware ESX Local Security Checks NASL id VMWARE_VMSA-2017-0021.NASL description a. ESXi, Workstation, and Fusion stack overflow via authenticated VNC session VMware ESXi, Workstation, and Fusion contain a vulnerability that could allow an authenticated VNC session to cause a stack overflow via a specific set of VNC packets. Successful exploitation of this issue could result in remote code execution in a virtual machine via the authenticated VNC session. Note: In order for exploitation to be possible in ESXi, VNC must be manually enabled in a virtual machine last seen 2020-06-01 modified 2020-06-02 plugin id 105410 published 2017-12-21 reporter This script is Copyright (C) 2017-2019 Tenable Network Security, Inc. source https://www.tenable.com/plugins/nessus/105410 title VMSA-2017-0021 : VMware ESXi, vCenter Server Appliance, Workstation and Fusion updates address multiple security vulnerabilities code # # (C) Tenable Network Security, Inc. # # The descriptive text and package checks in this plugin were # extracted from VMware Security Advisory 2017-0021. # The text itself is copyright (C) VMware Inc. # include("compat.inc"); if (description) { script_id(105410); script_version("3.11"); script_cvs_date("Date: 2019/09/26 15:14:18"); script_cve_id("CVE-2017-4933", "CVE-2017-4940", "CVE-2017-4941", "CVE-2017-4943"); script_xref(name:"VMSA", value:"2017-0021"); script_name(english:"VMSA-2017-0021 : VMware ESXi, vCenter Server Appliance, Workstation and Fusion updates address multiple security vulnerabilities"); script_summary(english:"Checks esxupdate output for the patches"); script_set_attribute( attribute:"synopsis", value: "The remote VMware ESXi host is missing one or more security-related patches." ); script_set_attribute( attribute:"description", value: "a. ESXi, Workstation, and Fusion stack overflow via authenticated VNC session VMware ESXi, Workstation, and Fusion contain a vulnerability that could allow an authenticated VNC session to cause a stack overflow via a specific set of VNC packets. Successful exploitation of this issue could result in remote code execution in a virtual machine via the authenticated VNC session. Note: In order for exploitation to be possible in ESXi, VNC must be manually enabled in a virtual machine's .vmx configuration file. In addition, ESXi must be configured to allow VNC traffic through the built-in firewall. VMware would like to thank Lilith Wyatt and another member of Cisco Talos for reporting this issue to us. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the identifier CVE-2017-4941 to this issue. b. ESXi, Workstation, and Fusion heap overflow via authenticated VNC session VMware ESXi, Workstation, and Fusion contain a vulnerability that could allow an authenticated VNC session to cause a heap overflow via a specific set of VNC packets resulting in heap corruption. Successful exploitation of this issue could result in remote code execution in a virtual machine via the authenticated VNC session. Note: In order for exploitation to be possible in ESXi, VNC must be manually enabled in a virtual machine's .vmx configuration file. In addition, ESXi must be configured to allow VNC traffic through the built-in firewall. VMware would like to thank Lilith Wyatt of Cisco Talos for reporting this issue to us. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the identifier CVE-2017-4933 to this issue. c. ESXi Host Client stored cross-site scripting vulnerability The ESXi Host Client contains a vulnerability that may allow for stored cross-site scripting (XSS). An attacker can exploit this vulnerability by injecting Javascript, which might get executed when other users access the Host Client. VMware would like to thank Alain Homewood of Insomnia Security for reporting this issue to us. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the identifier CVE-2017-4940 to this issue. d. Privilege escalation in vCenter Server Appliance (vCSA) VMware vCenter Server Appliance (vCSA) contains a local privilege escalation vulnerability via the 'showlog' plugin. Successful exploitation of this issue could result in a low privileged user gaining root level privileges over the appliance base OS. VMware would like to thank Lukasz Plonka for reporting this issue to us. The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the identifier CVE-2017-4943 to this issue." ); script_set_attribute( attribute:"see_also", value:"http://lists.vmware.com/pipermail/security-announce/2017/000394.html" ); script_set_attribute(attribute:"solution", value:"Apply the missing patches."); script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C"); script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C"); script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"); script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C"); script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available"); script_set_attribute(attribute:"exploit_available", value:"false"); script_set_attribute(attribute:"plugin_type", value:"local"); script_set_attribute(attribute:"cpe", value:"cpe:/o:vmware:esxi:5.5"); script_set_attribute(attribute:"cpe", value:"cpe:/o:vmware:esxi:6.0"); script_set_attribute(attribute:"cpe", value:"cpe:/o:vmware:esxi:6.5"); script_set_attribute(attribute:"patch_publication_date", value:"2017/12/19"); script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/21"); script_end_attributes(); script_category(ACT_GATHER_INFO); script_copyright(english:"This script is Copyright (C) 2017-2019 Tenable Network Security, Inc."); script_family(english:"VMware ESX Local Security Checks"); script_dependencies("ssh_get_info.nasl"); script_require_keys("Host/local_checks_enabled", "Host/VMware/release", "Host/VMware/version"); script_require_ports("Host/VMware/esxupdate", "Host/VMware/esxcli_software_vibs"); exit(0); } include("audit.inc"); include("vmware_esx_packages.inc"); if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED); if (!get_kb_item("Host/VMware/release")) audit(AUDIT_OS_NOT, "VMware ESX / ESXi"); if ( !get_kb_item("Host/VMware/esxcli_software_vibs") && !get_kb_item("Host/VMware/esxupdate") ) audit(AUDIT_PACKAGE_LIST_MISSING); init_esx_check(date:"2017-12-19"); flag = 0; if (esx_check(ver:"ESXi 5.5", vib:"VMware:esx-base:5.5.0-3.103.6480267")) flag++; if (esx_check(ver:"ESXi 5.5", vib:"VMware:esx-ui:1.12.0-6027315")) flag++; if (esx_check(ver:"ESXi 6.0", vib:"VMware:esx-base:6.0.0-3.76.6856897")) flag++; if (esx_check(ver:"ESXi 6.0", vib:"VMware:esx-ui:1.22.0-6282878")) flag++; if (esx_check(ver:"ESXi 6.0", vib:"VMware:vsan:6.0.0-3.76.6769077")) flag++; if (esx_check(ver:"ESXi 6.0", vib:"VMware:vsanhealth:6.0.0-3000000.3.0.3.76.6769078")) flag++; if (esx_check(ver:"ESXi 6.5", vib:"VMware:esx-base:6.5.0-1.29.6765664")) flag++; if (esx_check(ver:"ESXi 6.5", vib:"VMware:esx-tboot:6.5.0-1.29.6765664")) flag++; if (esx_check(ver:"ESXi 6.5", vib:"VMware:esx-ui:1.23.0-6506686")) flag++; if (esx_check(ver:"ESXi 6.5", vib:"VMware:vsan:6.5.0-1.29.6765666")) flag++; if (esx_check(ver:"ESXi 6.5", vib:"VMware:vsanhealth:6.5.0-1.29.6765667")) flag++; if (flag) { if (report_verbosity > 0) security_hole(port:0, extra:esx_report_get()); else security_hole(0); exit(0); } else audit(AUDIT_HOST_NOT, "affected");NASL family Misc. NASL id VMWARE_ESXI_VMSA-2017-0021.NASL description The remote VMware ESXi host is version 5.5, 6.0, or 6.5 and is missing a security patch. It is, therefore, affected by multiple vulnerabilities that can allow code execution in a virtual machine via the authenticated VNC session as well as cause information disclosure from one virtual machine to another virtual machine on the same host. last seen 2020-06-01 modified 2020-06-02 plugin id 105486 published 2017-12-29 reporter This script is Copyright (C) 2017-2019 and is owned by Tenable, Inc. or an Affiliate thereof. source https://www.tenable.com/plugins/nessus/105486 title ESXi 5.5 / 6.0 / 6.5 / Multiple Vulnerabilities (VMSA-2017-0021) (VMSA-2018-0002) (Spectre) (remote check)