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

Static analysis result for SHA-256 b90f1438270ef401…

MALICIOUS

Office (OOXML) / .XLSM

51.4 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: b8202c53964291d9f195ed04fcf2cb29 SHA-1: 3f3a9c11f19947975fb18658da46878245e41465 SHA-256: b90f1438270ef40109fb10fc418a2884832089f2a05a732ef4383ff98f2e8fde
320 Risk Score

Malware Insights

The file is an XLSM document containing VBA macros, specifically an Auto_Open macro, which is a common delivery mechanism. It exploits CVE-2017-11882 through an embedded Equation Editor object. This exploit attempts to execute a command-line stager, reconstructing the command as 'cmd /k REn %tmp%\qv&wsCRIpT %tmp%\v?.wsf', which likely downloads and executes a second-stage payload. The presence of the Equation Editor exploit and the macro-based execution strongly suggests a malicious dropper.

Heuristics 8

  • 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.
  • ClamAV: Doc.Dropper.Detected-9977031-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Detected-9977031-0
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • Suspicious extracted artifact high 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.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
61e2a42a90d4af63810c7617d62899c5d5d54d220cc9d19b99ecacc2d3ef6d76		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 20982 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.
ooxml_oleobject_00.bin
35bba1a9790b1f63c0d1fba77923b84b962a8bb2ff476552277559ea58a4b3d4		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 13312 bytes
ooxml_oleobject_00_ole10native_00.bin
1d83e08c2dae80083ee45ebb95d35bc6056528139cc45e4aab7531eaa03a6ea9		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 10323 bytes
ooxml_oleobject_01.bin
f2b74688984f68399019cf7d7bdaaf5f54ccef6f67582845360470becb72c2cc		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 15872 bytes
ooxml_oleobject_01_ole10native_00.bin
294c7393ba1bb19e2e4cf05cbef14d79ee93cee6d6a9db916546474d40d6f62b		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 12866 bytes
ooxml_oleobject_02.bin
509828e962babb9f383dd8ac2e56c55a4a1747019a6406152e4e66bdad4f0225		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_03.bin
5581840ed17acc08ad320af637b71a3b659476e651339e5fb5c71a688eddcf37		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 50176 bytes
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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