Jaff — Office (OOXML) / .DOCX malware analysis

Static analysis result for SHA-256 5a6e3c7fb8aa9dcd…

MALICIOUS

Office (OOXML) / .DOCX

65.8 KB Created: 2017-06-22 10:05:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: 6d03504c0b4f2973b01b653cd34f0c86 SHA-1: 3976dcf12f1445d21deb3930b8cf680b82bfdec2 SHA-256: 5a6e3c7fb8aa9dcde2a73c52ef7581679c629433bad32db53d9dd6c02023b3c9
402 Risk Score

Malware Insights

Jaff · confidence 95%

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

The sample is a malicious OOXML document containing a heavily obfuscated VBA macro. The macro utilizes `CreateObject` and `CallByName` functions, indicative of a downloader. ClamAV signatures confirm it as 'Doc.Downloader.Jaff-6329915-0', suggesting the Jaff family. The `Document_Open` macro is designed to execute automatically, likely to download and run a secondary payload.

Heuristics 10

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Doc.Downloader.Jaff-6329915-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Jaff-6329915-0
  • 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.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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 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 http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.microsoft.com/office/drawing/2014/chartex
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2012/wordml
    • http://schemas.microsoft.com/office/word/2015/wordml/symex
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
5437baa6dbe1e2377ce7b1fff9c925268a1f01068e19a7e295caa351f9903236		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 19701 bytes
vbaProject_00.bin
4dda95d1417cb70ae0cc36392b53b1d841316092387efa7426f0be59ddc79d65		 vba-project OOXML VBA project: word/vbaProject.bin 77312 bytes
Detection
ClamAV: Doc.Downloader.Jaff-6329915-0
Obfuscation or payload: unlikely

Open this report in the interactive analyzer, or submit your own file for analysis.