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

Static analysis result for SHA-256 6f0e4f098431a0fb…

MALICIOUS

Office (OOXML) / .XLSM

55.1 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: 661dc9e7d21a951297fd083560131b32 SHA-1: 4281a2d2517a33aba434193c26bd44057e52084d SHA-256: 6f0e4f098431a0fb1e439f1d24b7ce8861bb6d9ac5caedc6784c9c42019eb9fc
442 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an XLSM file containing VBA macros, including an Auto_Open macro that utilizes CreateObject. Critical heuristics indicate the exploitation of CVE-2017-11882 via an Equation Editor OLE object, which is known to execute arbitrary commands. This suggests the document is designed to exploit this vulnerability to download and execute a secondary payload, likely leading to further system compromise.

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
1855a18ea2711fd29f34d2045927d6311f9c51b8beaaa59fb1982f95e57c70ea		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 62404 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
ooxml_oleobject_00.bin
a58e5873e0ac40724b1e1e009191c42fd9b41572e9f3fadede0f5f1342358014		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 27648 bytes
ooxml_oleobject_00_ole10native_00.bin
53addbf45b3deec2a112328adfb1c7f826774e29b97f2fd7d19e14ba539a428b		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 24868 bytes
ooxml_oleobject_01.bin
27cd04a06d02982bcc65401c128b67ade1c3051d2ac37c2cf3d68cdf9a3b535f		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 22016 bytes
ooxml_oleobject_01_ole10native_00.bin
d8a2170b4311cb6ab60449e289c3a088b36c0db4cc29cdd66559e4fa3bd3ceb7		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 19288 bytes
ooxml_oleobject_02.bin
b505e1e3134835067d1d87f3294ff3eac111369fe9a81ace166af4faa9fcb51a		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_03.bin
3348b024617fb23dd3194bc3e583b65244d65718fb171330296d4c077d89fdcf		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 88576 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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