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

Static analysis result for SHA-256 c1762c0acb5d99a1…

MALICIOUS

Office (OOXML) / .XLSM

53.2 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: 31c153af18518eb1554971bb0e39a90f SHA-1: ef50ade88e947cb7e88526e583235ee94417b41c SHA-256: c1762c0acb5d99a17b7fe711c9320ec24e688a5cc5b88cd7425cba02ea94e005
380 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.005 Visual Basic

The sample is an XLSM file containing VBA macros, including an Auto_Open macro, which is a common delivery mechanism. It exploits CVE-2017-11882 through an embedded Equation Editor object. The embedded Equation Editor object contains a command stager that attempts to execute a script from a temporary file, likely downloading and running a second-stage payload. ClamAV detections further confirm its malicious nature as a dropper.

Heuristics 9

  • 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
  • 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
  • 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
68b0155a27b0414022758f7e217b33124bb406440135ea71cc4bbbbad1a8c908		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 41358 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
a8241b97edee9dd5eea0f227e1d9efbf5b10a7b9cf976006bb3dbc255632d609		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_01.bin
8925340df6d01bab59eaaa1c09419dea39787fbfefd14650799dcd2190356bd1		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 22016 bytes
ooxml_oleobject_01_ole10native_00.bin
3614db1093e69aa3c2c82c673e69d281e360a705e0bdf854731c9e29b4cf8348		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 19177 bytes
ooxml_oleobject_02.bin
10f1d716557ee1c0cb2c40ec6c83201cb57e912555d027bd4110a615fb65ba77		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 27136 bytes
ooxml_oleobject_02_ole10native_00.bin
d312d16d81440574e8850795b71250bf914e29e973eaea3c0214779be6e3dffb		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 24109 bytes
ooxml_oleobject_03.bin
964a795bff55aff319cdb0a0d27d350ed6292ce235b063cc0637073875942c55		 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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