Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 132f4bbf95fd376b…

MALICIOUS

Office (OOXML) / .XLSM

53.2 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: ce42d97d7c3430b80646ad03019d892b SHA-1: 54e7dbe4fa398ce0e2756cd1faf9923ee8dc1e6e SHA-256: 132f4bbf95fd376b3f4a6f9eeec2d12b9f8bbdba33436a1e9514eef7f47a4d37
442 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic

This XLSM file contains a VBA macro with an Auto_Open subroutine that leverages the CVE-2017-11882 vulnerability in the Equation Editor OLE object. The embedded script attempts to execute a command that downloads and runs a second-stage payload from a temporary file. The presence of the Equation Editor exploit and the VBA auto-execution strongly indicate malicious intent.

Heuristics 11

  • CVE-2017-11882 — Equation Editor command stager critical CVE likely CVE_2017_11882_EQUATION_NATIVE_CMD
    Embedded Equation Editor OLE data contains an invalid Equation Native/MTEF stream with an embedded command stager. This is likely CVE-2017-11882 exploitation because the vulnerable Equation Editor component is reached and the malformed native stream directly carries process-launch bytes.
  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject3.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Embedded Office object carries macros critical OFFICE_EMBEDDED_MACRO_OBJECT
    This document embeds a second Office file that itself contains a VBA macro project or an Excel 4.0 (XLM) macro sheet. Hiding a macro-bearing workbook or document inside another document — frequently under an obfuscated, non-standard part name — is a macro-smuggling technique that defeats scanners which only inspect the outer document's macro storage. No benign authoring workflow stages a hidden macro project this way.
  • ClamAV: Doc.Dropper.Detected-9977031-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Detected-9977031-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
468c46167f5656209d84551b4da37deed10951241a8bbf95c5d1a145bf95b308		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 41366 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
ooxml_oleobject_00.bin
8925340df6d01bab59eaaa1c09419dea39787fbfefd14650799dcd2190356bd1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 22016 bytes
ooxml_oleobject_00_ole10native_00.bin
3614db1093e69aa3c2c82c673e69d281e360a705e0bdf854731c9e29b4cf8348		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 19177 bytes
ooxml_oleobject_01.bin
6d562c1cd88f8bf50390bb43793863e88b39f7fe83cec537abbc9c0b17047c6d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 27136 bytes
ooxml_oleobject_01_ole10native_00.bin
5054b7642f4edfbbfab6f009730b8186482676049553b23df62d53c65a0de58b		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 24117 bytes
ooxml_oleobject_02.bin
a8241b97edee9dd5eea0f227e1d9efbf5b10a7b9cf976006bb3dbc255632d609		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_03.bin
4531348d58aa1f447da4d0c9893689501fb6430a2bfe64abddeea5c2cda45567		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 65536 bytes
Detection
ClamAV: Doc.Dropper.Detected-9977031-0
Obfuscation or payload: unlikely
emf_00.emf
979dde2aed02f077c16ae53546c6df9eed40e8386d6db6fc36aee9f966d2cb82		 ooxml-emf OOXML EMF part: xl/media/image1.emf 4968 bytes
emf_01.emf
4d4d1e7b04c99dcb8e885915068ad6f74cc2333e91580cdae5ccaa00c427247f		 ooxml-emf OOXML EMF part: xl/media/image2.emf 1536 bytes

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