Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 7a9c90f8e2093f60…

MALICIOUS

Office (OLE) / .XLS

339.5 KB Created: 2021-12-17 13:23:39 Authoring application: Microsoft Excel@羀䶍Ǘ@ሀ㌾Ǘ
MD5: 9c4c0304f41d3b1df8b9a7de00f255a5 SHA-1: 2aeb4afdd388e725cbd693c043da73bd3a4518a1 SHA-256: 7a9c90f8e2093f60fe60e8f0737b8ae99b16a4a4a39e3454ed058d6e9b223142
302 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled spreadsheet that uses an 'enable content' lure to prompt the user to run macros. The Auto_Open macro reconstructs and executes the command 'mshta.exe C:\ProgramData\AjdjQN...b.rtf', indicating it attempts to download and execute a second-stage payload. The use of ShellExecute and mshta.exe are common techniques for malware delivery.

Heuristics 8

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • URL reconstructed from XLM cell array (3 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://cdn.discordapp.com/attachments/912724343694450701/923232583574249502/XelQMYjjXMXqzjesusismyfriend.bin
    • https://cdn.discordapp.com/attachments/912724343694450701/923232967109804032/RktsZjesusismyfriend.bin
    • https://cdn.discordapp.com/attachments/912722552516902995/923233383256039464/QhgnnYRojesusismyfriend.bin

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1d6eb875e2a161070ff697d9d56ddbccb417abcc83b2112e1f64af7c096dabd6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1738 bytes

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