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

Static analysis result for SHA-256 55fbf836924235ba…

MALICIOUS

Office (OOXML) / .XLSM

671.1 KB Created: 2015-01-15 16:55:01 UTC Authoring application: Microsoft Excel 12.0000
MD5: 91d5eb02a5544e4a1d5ff75e45574a89 SHA-1: cf064dcfaa3901c51fb234818c90a4c946a56578 SHA-256: 55fbf836924235baf94148c414dbeb7d308a25787ba94d870574b8ddb25e17dd
418 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

This XLSM file contains a Workbook_Open macro that attempts to disable VBA warnings and then calls MPS. The macro also utilizes WScript.Shell and CreateObject, indicating it likely downloads and executes a second-stage payload. The presence of an Equation Editor OLE object with anomalous native stream data, specifically triggering CVE-2018-0798, strongly suggests exploitation of this vulnerability to achieve code execution.

Heuristics 13

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • 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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 2 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://www.dropbox.com/s/zhp1b06imehwylq/Synaptics.rar?dl=1
    • https://www.dropbox.com/s/zhp1b06imehwylq/Synaptics.rar?dl=1�
    • https://docs.google.com/uc?id=0BxsMXGfPIZfSVzUyaHFYVkQxeFk&export=download
    • https://docs.google.com/uc?id=0BxsMXGfPIZfSVzUyaHFYVkQxeFk&export=download�

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
e641847ccb4454ae8aee6b764f337d2b79450fb4ece918c9383e8430c4552946		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 6480 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 shell/COM execution token(s). Carved macro source contains an auto-exec entry point and execution/download terms.
ooxml_oleobject_00.bin
2ad5ab6f86ad4ef77c515b5cf17fcb3c918d3a496d9980148e7d52f54e9fb367		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 949760 bytes
ooxml_oleobject_00_ole10native_00.bin
9d8e5aeb94f7f9a9bcb20962ecaa866f9d1ee3fe32645b6c1d98849555bb7c6f		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10naTiVe 940696 bytes
ooxml_oleobject_01.bin
31fdc7a65bcfc43b3ce5a79db6b2770a53be5fa1d2298c8aefa72ad8f02977c1		 ooxml-ole-object OOXML embedded OLE part: xl/vbaProject.bin 24576 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.

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