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

Static analysis result for SHA-256 15b34cc0ce855b44…

MALICIOUS

Office (OOXML) / .XLSM

46.9 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: be304fc5ffaee4b897b41a1d15b91b95 SHA-1: 67f073cdd1326b36e620abf6ab319fac6399ef77 SHA-256: 15b34cc0ce855b44c423c8f9721473bd914a0b183a40ee5478e526e3a8c7a292
442 Risk Score

Malware Insights

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

The critical heuristic CVE_2017_11882_EQUATION_NATIVE_CMD indicates exploitation of the Equation Editor vulnerability. The Auto_Open macro and CreateObject calls suggest the VBA code is designed to execute a payload. The extracted command line `cmd /c ren %tmp%\mm v&cSCripT %tmp%\v..wsf ..C.......................................................` indicates the stager attempts to rename a file and then execute a script, likely to download and run a second-stage payload.

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: Xls.Malware.Generic-8058593-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Generic-8058593-0
  • 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
5b49be9122936f3b08286ac80d6ace50b6356b63389a3298b67e01c6538d9de4		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 27626 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
ooxml_oleobject_00.bin
a584b820a2992d568309d29a53553719335cf38a9df44dc68a0604a6cca73f49		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 3584 bytes
ooxml_oleobject_00_ole10native_00.bin
f6cb57a07162be208979a032f45da4c4f20a53852a8066e47c23f6ed11fac834		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 1275 bytes
ooxml_oleobject_01.bin
a3744ee795040893ff0f6f6f0294c79e77b4adcb20de320cc05040edf6ef5ed5		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_02.bin
2fe226fd0f5a1be6f7bed5b0b09362ae77308330aa9f442a1847c5743c68e993		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 12288 bytes
ooxml_oleobject_02_ole10native_00.bin
d90f757eba7c4b60e98ad4f4c46a92e853b6e665e1aeeda76a535f75cb478788		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 9473 bytes
ooxml_oleobject_03.bin
8eeeb7893cda73660e89d3713068807dc7c73fd52112dfe95288454c3454859b		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 46080 bytes
Detection
ClamAV: Xls.Malware.Generic-8058593-0
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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