expat 2.2.1/2.2.2 on Windows xmlparse.c writeRandomBytes_RtlGenRandom untrusted search path

HistoryDiffrelatejsonxmlCTI

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability identified as problematic has been detected in expat 2.2.1/2.2.2 on Windows. Affected is the function writeRandomBytes_RtlGenRandom in the library ADVAPI32.DLL of the file xmlparse.c. Performing a manipulation results in untrusted search path. This vulnerability is identified as CVE-2017-11742. The attack is only possible with local access. There is not any exploit available.

Detailsinfo

A vulnerability was found in expat 2.2.1/2.2.2 on Windows. It has been classified as problematic. This affects the function writeRandomBytes_RtlGenRandom in the library ADVAPI32.DLL of the file xmlparse.c. The manipulation with an unknown input leads to a untrusted search path vulnerability. CWE is classifying the issue as CWE-426. The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The writeRandomBytes_RtlGenRandom function in xmlparse.c in libexpat in Expat 2.2.1 and 2.2.2 on Windows allows local users to gain privileges via a Trojan horse ADVAPI32.DLL in the current working directory because of an untrusted search path, aka DLL hijacking.

The bug was discovered 07/15/2017. The weakness was released 07/30/2017 by Basti (GitHub Repository). It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2017-11742 since 07/30/2017. Attacking locally is a requirement. A authentication is required for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1574 according to MITRE ATT&CK.

The vulnerability was handled as a non-public zero-day exploit for at least 15 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at SecurityFocus (BID 100147†). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Name

expat

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 4.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Untrusted search path
CWE: CWE-426
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

07/15/2017 🔍
07/30/2017 +15 days 🔍
07/30/2017 +0 days 🔍
07/30/2017 +0 days 🔍
07/30/2017 +0 days 🔍
08/07/2017 +8 days 🔍
12/14/2022 +1955 days 🔍

Sourcesinfo

Advisory: 82
Researcher: Sebastian. (Basti)
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-11742 (🔍)
GCVE (CVE): GCVE-0-2017-11742
GCVE (VulDB): GCVE-100-104631
SecurityFocus: 100147 - Libexpat Expat CVE-2017-11742 DLL Loading Remote Code Execution Vulnerability

Entryinfo

Created: 07/30/2017 21:19
Updated: 12/14/2022 12:55
Changes: 07/30/2017 21:19 (63), 11/02/2019 10:41 (5), 01/06/2021 17:00 (2), 12/14/2022 12:55 (3)
Complete: 🔍
Cache ID: 216::103