Microsoft Internet Explorer 9/10/11 Scripting Engine LastParen information disclosure

CVSS Meta Temp Score
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CTI Interest Score
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4.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft Internet Explorer 9/10/11. It has been classified as critical. The impacted element is the function jscript!RegExpFncObj::LastParen of the component Scripting Engine. Performing a manipulation results in information disclosure. This vulnerability is known as CVE-2017-11906. Remote exploitation of the attack is possible. Furthermore, an exploit is available. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability was found in Microsoft Internet Explorer 9/10/11 (Web Browser). It has been classified as problematic. This affects the function jscript!RegExpFncObj::LastParen of the component Scripting Engine. The manipulation with an unknown input leads to a information disclosure vulnerability. CWE is classifying the issue as CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. This is going to have an impact on confidentiality. The summary by CVE is:

Internet Explorer in Microsoft Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, and Windows 10 Gold, 1511, 1607, 1703, 1709, and Windows Server 2016 allows an attacker to obtain information to further compromise the user's system, due to how Internet Explorer handles objects in memory, aka "Scripting Engine Information Disclosure Vulnerability". This CVE ID is unique from CVE-2017-11887 and CVE-2017-11919.

The bug was discovered 12/12/2017. The weakness was published 12/12/2017 by Ivan Fratric with Google Project Zero as KB4053580 as confirmed security update guide (Website). It is possible to read the advisory at portal.msrc.microsoft.com. This vulnerability is uniquely identified as CVE-2017-11906 since 07/31/2017. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details and a public exploit are known. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK. The advisory points out:

An information disclosure vulnerability exists when Internet Explorer improperly handles objects in memory. An attacker who successfully exploited the vulnerability could obtain information to further compromise the user’s system.

A public exploit has been developed by Google Security Research and been published 1 weeks after the advisory. The exploit is shared for download at exploit-db.com. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 105184 (Windows 7 and Windows Server 2008 R2 December 2017 Security Updates), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Windows : Microsoft Bulletins and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 100325 (Microsoft Internet Explorer Security Update for December 2017). The code used by the exploit is:

<!-- saved from url=(0014)about:internet -->
<meta http-equiv="X-UA-Compatible" content="IE=8"></meta>
<script language="Jscript.Encode">
 
function go() {
  var r= new RegExp(Array(100).join('()'));
  ''.search(r);
  alert(RegExp.lastParen);
}
 
go();
 
</script>

Applying the patch KB4053580 is able to eliminate this problem. The bugfix is ready for download at catalog.update.microsoft.com. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (43372), Tenable (105184) and SecurityFocus (BID 102078†). Similar entries are available at VDB-110522, VDB-110523, VDB-110524 and VDB-110527. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.5

VulDB Base Score: 4.3
VulDB Temp Score: 3.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 4.3
Vendor Vector (Microsoft): 🔍

NVD Base Score: 5.3
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Google Security Research
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 105184
Nessus Name: Windows 7 and Windows Server 2008 R2 December 2017 Security Updates
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 863099
OpenVAS Name: Microsoft Internet Explorer Multiple Vulnerabilities (KB4052978)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

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Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
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Exploit Delay Time: 🔍

Patch: KB4053580

Timelineinfo

07/31/2017 🔍
12/12/2017 +134 days 🔍
12/12/2017 +0 days 🔍
12/12/2017 +0 days 🔍
12/12/2017 +0 days 🔍
12/12/2017 +0 days 🔍
12/12/2017 +0 days 🔍
12/13/2017 +1 days 🔍
12/19/2017 +6 days 🔍
12/19/2017 +0 days 🔍
12/29/2025 +2932 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: KB4053580
Researcher: Ivan Fratric
Organization: Google Project Zero
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-11906 (🔍)
GCVE (CVE): GCVE-0-2017-11906
GCVE (VulDB): GCVE-100-110535

OVAL: 🔍

SecurityFocus: 102078 - Microsoft Internet Explorer Scripting Engine CVE-2017-11906 Information Disclosure Vulnerability
SecurityTracker: 1039993

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 12/13/2017 07:53
Updated: 12/29/2025 21:15
Changes: 12/13/2017 07:53 (102), 12/16/2019 11:11 (7), 01/27/2021 06:56 (3), 12/29/2025 21:15 (15)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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