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

Static analysis result for SHA-256 5b76f37e407cb88f…

MALICIOUS

Office (OOXML) / .XLSM

48.6 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000
MD5: a8358a84a11cfbbc9dc53f7f86f81395 SHA-1: a53f0ab229a8fa3ae98ba1029079ebc13c9edea1 SHA-256: 5b76f37e407cb88f6e33cadd2ef5be1cca9dde9c31e881b9a583d6f0a231ca41
442 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.003 Command and Scripting Interpreter: Windows Command Shell

The file is an Excel macro-enabled spreadsheet (XLSM) containing an embedded Equation Editor OLE object. This object exploits CVE-2017-11882 to execute a command-line stager. The stager appears to rename a file and then execute a WScript 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.Dropper.Sdrop-9451844-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Sdrop-9451844-0
  • 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
fbda84d7d33de61760a2025121f6b42abb6cf091d8c688ed232a8d11284b6f89		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 29236 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
af683479f2fdb91fa368a0490abda2e04cd3edcc1fc6eb210a545dc80b66dd34		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 12800 bytes
ooxml_oleobject_00_ole10native_00.bin
68f543a5ce981bd57eeaa253ef083a98d8596a2b4e22cc25792ec3fb7dd5b4a7		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 10205 bytes
ooxml_oleobject_01.bin
671c85466cdb8a263da36abdd94134735f4b2a2eff366a56f630d015322c0f7c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject3.bin 5936 bytes
ooxml_oleobject_02.bin
df1b8f667f31a5b25f91257d3dae1cd6691dbcb8bf54e6e915384e1a79f24ec6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 3584 bytes
ooxml_oleobject_02_ole10native_00.bin
56fc5dcef6ff07d4be955fd8a78580ec0f16d8e50dbe9d700b72ba9f09b62e60		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native 1281 bytes
ooxml_oleobject_03.bin
93b8d5f916e068ac22d2b79afe5649b59dd81f21e86dc2b924ffc7b491d54dea		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 52736 bytes
Detection
ClamAV: Xls.Dropper.Sdrop-9451844-0
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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