cbcvebase.
CVE-2018-8631
published 2018-12-12

CVE-2018-8631: A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory, aka "Internet Explorer Memory Corruption…

PriorityP269high7.5CVSS 3.0
AVNACHPRNUIRSUCHIHAH
EXPLOIT
EPSS
69.21%
99.3th percentile
A remote code execution vulnerability exists when Internet Explorer improperly accesses objects in memory, aka "Internet Explorer Memory Corruption Vulnerability." This affects Internet Explorer 9, Internet Explorer 11, Internet Explorer 10.

Affected

33 ranges· showing 25
VendorProductVersion rangeFixed in
microsoftinternet_explorer
microsoftinternet_explorer
microsoftinternet_explorer
microsoftinternet_explorer_10
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11
microsoftinternet_explorer_11

Detection & IOCsextracted from sources · hover to see the quote

  • The vulnerability is triggered via jscript!JsArrayFunctionHeapSort — an out-of-bounds write occurs when Array.prototype.sort is called on an 'arguments' object set as a function prototype, causing memory corruption in jscript.dll
  • Crash stack trace bottoms out in jscript!JsArrayFunctionHeapSort+0xe2 / jscript!JsArraySort — monitor for abnormal jscript.dll call stacks involving JsArrayFunctionHeapSort leading to out-of-bounds heap writes in Internet Explorer
  • Heap allocation for the sort operation originates from jscript!JsArrayFunctionHeapSort+0x79 (malloc wrapper) — heap page fault / verifier hit at this offset is a strong indicator of exploitation
  • Exploit delivery vector is a specially crafted website loaded in Internet Explorer; monitor for IE processes spawning unexpected child processes or making unusual network connections after visiting attacker-controlled or compromised web pages
  • CVE-2018-8631 was rated 'Exploitation More Likely' by Microsoft for both latest and older software releases — prioritise detection on Internet Explorer 9, 10, and 11 across all supported Windows versions
  • ·The proof-of-concept triggers the bug in jscript.dll (legacy JScript engine used by IE in quirks/compatibility mode); the vulnerability affects Internet Explorer 9, 10, and 11 — Edge is not affected
  • ·Exploitation requires user interaction — the attacker must convince the user to visit a malicious page or open a malicious attachment; no drive-by without user action is possible
  • ·Impact is bounded by the current user's privilege level — if the user is not an administrator, the attacker cannot fully take over the system without a separate privilege escalation step

CVSS provenance

nvdv3.07.5HIGHCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.07.6HIGHAV:N/AC:H/Au:N/C:C/I:C/A:C
vendor_msrc6.4MEDIUM
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