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Sid 1-46951

Message

BROWSER-IE Microsoft Internet Explorer 11 JScript use-after-free attempt

Summary

This event is generated when a user using Microsoft Internet Explorer 11 accesses a page where JavaScript modifies a variable that is reused when not handled by garbage collection.

Impact

Attempted User Privilege Gain

CVE-2018-8267:

CVSS base score 7.5

CVSS impact score 5.9

CVSS exploitability score 1.6

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Detailed information

CVE-2018-8267 is a use after free vulnerability in the Jscript scripting engine (jscript.dll) of Windows. The root cause is where a VAR points to an object, and the object is freed because its not rooted in the GC. CVE-2018-8267: A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka "Scripting Engine Memory Corruption Vulnerability." This affects Internet Explorer 9, Internet Explorer 11, Internet Explorer 10. This CVE ID is unique from CVE-2018-8243.

Affected systems

  • microsoft internet_explorer 9
  • microsoft internet_explorer 10
  • microsoft internet_explorer 11

Ease of attack

Simple, it is not known if any exploits exist for this.

False positives

None known.

False negatives

None known.

Corrective action

Follow corporate patching procedures to ensure Microsoft Internet Explorer is up to date.

Contributors

  • Cisco's Talos Intelligence Group

Additional References

  • portal.msrc.microsoft.com/en-us/security-guidance/advisory/CVE-2018-8267