Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 4262099627a80778…

MALICIOUS

Office (OOXML)

10.4 KB
MD5: d9a67d08a97a39094318f777bdb586ae SHA-1: 26cb79d9998f5d36e88e08bd09897061bc8a7dd5 SHA-256: 4262099627a8077855cae93e619f21c6b245b8c6a8592091c031ef942f91915e
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The OOXML document contains a VBA macro that is automatically executed upon opening due to the presence of an Auto_Open subroutine. This macro utilizes ShellExecuteA via the 'Dainava' alias to execute a PowerShell command. The critical heuristic indicates that the 'powershell' keyword was reassembled from split string literals, suggesting obfuscation. The primary purpose of this script is to download and execute a second-stage payload, as indicated by the execution tokens and the use of ShellExecuteA.

Heuristics 5

  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • 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 (project part renamed away from vbaProject.bin: ppt/aodkaoskd.b)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
f6ed5b6c3cd27ab3fc97a32bd815eb2476a2be9f11e520cc57ceb69c621f254d		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2444 bytes
vbaProject_00.bin
bedb6e4e73ca891e632b79114d0a3decb7079a77d07d6d72375e13de9c8d74d1		 vba-project OOXML VBA project: ppt/aodkaoskd.b 23040 bytes

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