Dridex — Office (OOXML) malware analysis

Static analysis result for SHA-256 55c5773d32dffce2…

MALICIOUS

Office (OOXML)

256.6 KB Created: 2021-03-08 16:24:19 UTC Authoring application: Microsoft Excel 15.0300
MD5: 5277696ea56d3d22b237b4a93a77487c SHA-1: ab44385e29c67ee7d424a7f9d29d9c54f1814de7 SHA-256: 55c5773d32dffce268e56a822b04fd896cc5c6193e43a7f52eeacd5ebd23c169
330 Risk Score

Malware Insights

Dridex · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains a Workbook_Open macro that executes obfuscated VBA code. This code utilizes GetObject and Environ calls, indicative of a loader. The ClamAV detection and heuristic firings strongly suggest this is a Dridex dropper variant. The VBA code likely attempts to download and execute a second-stage payload from one of the embedded URLs.

Heuristics 9

  • 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.Dropper.Dridex-9845759-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Dridex-9845759-0
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • 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://turktech.co.uk/wp-content/uploads/2020/01/XBKtCe6h.php
    • https://lweonepal.com/wp-content/cache/object/013/bFPs28xfQyOe.php
    • https://birkett.com.au/include/Base/Modules/Filter/KZyRSXJtoC.php
    • https://dikan.co.za/wsz2SCI6sU6k6o.php
    • https://sproca.tg/wp-content/themes/agronomics-lite/css/nj6N9LQhADNC.php
    • https://triplonet.com.br/__MACOSX/wp-includes/js/codemirror/3Uqzx5RTyl8pT.php
    • https://new.bombill.com/B2B/js/public_html/new.bombill.com/kML98YVm1.php
    • https://askcon.net/wp-includes/SimplePie/Content/Type/0lOzUuHLScUH.php
    • https://fortgem.co.uk/wp-includes/css/dist/block-directory/Pk57G2yz.php
    • https://slaweskicpa.com/tmp/install_5a4f05d42cc52/install_5a4f05f303fa0/backend/vlvzskOj4To9.php
    • http://www.w3.org/1999/XSL/Transform

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
a6ad8f6c423f0aa5d1bae737aa8896de46d0884127642b3ef6d19e6ba9973792		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 15577 bytes
vbaProject_00.bin
e39dbb7f4eee8b695305d4f626892acb666a83108073ef9671a6b0216daacfc3		 vba-project OOXML VBA project: xl/vbaProject.bin 67072 bytes
Detection
ClamAV: Doc.Dropper.Dridex-9845759-0
Obfuscation or payload: unlikely

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