cbcvebase.
CVE-2018-8552
published 2018-11-14

CVE-2018-8552: An information disclosure vulnerability exists when VBScript improperly discloses the contents of its memory, which could provide an attacker with information…

PriorityP264high7.5CVSS 3.0
AVNACHPRNUIRSUCHIHAH
EXPLOIT
EPSS
50.96%
98.8th percentile
An information disclosure vulnerability exists when VBScript improperly discloses the contents of its memory, which could provide an attacker with information to further compromise the user's computer or data, aka "Windows Scripting Engine 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

commandCall Filter(arr, "a")
  • Crash/OOB read occurs inside vbscript!rtFilter when a VBScript array containing a class object with a Default Property that calls ReDim is passed to the Filter() function — look for VBScript executing Filter() on arrays containing class instances with Default Property accessors that resize arrays.
  • The fault manifests as an access violation in OLEAUT32!VariantCopy called from vbscript!rtFilter+0x183, reading from an unmapped/invalid memory page — crash signature: OLEAUT32!VariantCopy+0xb with esi pointing to an invalid address (e.g. 0d9cf000).
  • The exploit uses 'On Error Resume Next' to suppress errors and keep execution going after the OOB read — VBScript with this directive combined with Filter() calls on heterogeneous arrays (mixing strings and class objects) should be treated as suspicious.
  • Exploitation vector is a web-based attack via Internet Explorer (IE 9/10/11) or an ActiveX control marked 'safe for initialization' embedded in an Office document hosting the IE rendering engine — monitor for iexplore.exe spawning child processes or unusual memory reads from vbscript.dll.
  • ·The exploit PoC uses 'On Error Resume Next' which suppresses the crash in-process; in a weaponized exploit the OOB read would be leveraged for information disclosure to bypass ASLR/DEP rather than causing an immediate visible crash — detection based solely on crash telemetry may miss exploitation.
  • ·The vulnerability is an out-of-bounds read (information disclosure) in vbscript!rtFilter, not a direct write primitive — exploitation requires chaining with additional techniques to achieve code execution.

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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