Vulnerabilities > CVE-2017-0055 - Cross-site Scripting vulnerability in Microsoft products
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
LOW Integrity impact
LOW Availability impact
NONE Summary
Microsoft Internet Information Server (IIS) in Windows Vista SP2; Windows Server 2008 SP2 and R2; Windows 7 SP1; Windows 8.1; Windows Server 2012 Gold and R2; Windows RT 8.1; Windows 10 Gold, 1511, and 1607; and Windows Server 2016 allows remote attackers to perform cross-site scripting and run script with local user privileges via a crafted request, aka "Microsoft IIS Server XSS Elevation of Privilege Vulnerability."
Vulnerable Configurations
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 | Windows : Microsoft Bulletins |
| NASL id | SMB_NT_MS17-016.NASL |
| description | The remote Windows host is missing a security update. It is, therefore, affected by a cross-site scripting (XSS) vulnerability due to improper validation of user-supplied input. An unauthenticated, remote attacker can exploit this, via a specially crafted request, to execute arbitrary script code in a user |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 97741 |
| published | 2017-03-15 |
| 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/97741 |
| title | MS17-016: Security Update for Windows IIS (4013074) |
| code | |
Packetstorm
| data source | https://packetstormsecurity.com/files/download/141671/msiis-xss.txt |
| id | PACKETSTORM:141671 |
| last seen | 2017-03-17 |
| published | 2017-03-16 |
| reporter | David Fernandez |
| source | https://packetstormsecurity.com/files/141671/Microsoft-Internet-Information-Services-Cross-Site-Scripting.html |
| title | Microsoft Internet Information Services Cross Site Scripting |
Seebug
| bulletinFamily | exploit |
| description | During a penetration test against the infrastructure of one of our clients we discovered a reflected Cross Site Scripting/HTML injection vulnerability in Microsoft Internet Information Services web server. The vulnerability could be exploited, with the help of user interaction, to inject javascript or html code in the browser of the victim in the context of a website hosted on IIS. #### Versions Affected * MS Internet Information services as deployed in the following Windows versions: * Windows Vista * Windows 7 * Windows 8.1 and RT 8.1 * Windows 2008 and 2008 r2 * Windows 2012 and 2012 r2 * Windows 2016 #### CVE Reference CVE-2017-0055 Vendor Fix Microsoft released bulletin MS017-16 and associated patches for each affected version #### Vulnerability Type XSS Elevation of Privilege #### Severity Rating Important #### Description The default HTTP 500.19 error page of Internet Information Services fails to properly sanitize user-supplied input as rendered in the path where the Web.config file of the application or directory was attempted to be loaded. Under normal conditions, any attempt to craft and visit an URL including javascript or html content on it will trigger either an HTTP 400 response from the server or will be handled by the customErrors Web.config setting of the application. We discovered that, if a website root hosted on IIS or any subfolder on it is located in a UNC path (NAS, shared folder or mapped drive), it is possible to craft a special link that, upon clicked, will trigger an HTTP 500.19 error page from the server rendering the javascript or html code injected as part of the path where the Web.config file was attempted to be loaded. As the flaw lies in the fact of the improper sanitization of the 500.19 error page, other attack vectors not requiring UNC paths might exist. #### Impact By inducing a victim to click on a specially crafted link, is possible to execute javascript code in the victim’s browser in the context of a website hosted on IIS to conduct a classical reflected Cross Site Scripting (XSS) attack. The impact could be stealing user cookies, hijacking user session or performing unauthorized actions in the web application on behalf of the victim. If the code injected is HTML, the vulnerability allows to conduct phishing attacks using the legitimate website against web application users. #### Proof of concept ```http://vulnerableiis/uncpath/%3Cimg%20onerror=alert('xss')%20src=/%3E:/```  #### Mitigations Neither ValidateRequest nor configuring customErrors setting on Web.config will protect from this, as this happens earlier in the request processing pipeline. |
| id | SSV:93099 |
| last seen | 2017-11-19 |
| modified | 2017-05-12 |
| published | 2017-05-12 |
| reporter | Root |
| title | Microsoft IIS Server XSS Vulnerability(CVE-2017-0055) |