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

Static analysis result for SHA-256 13c9bc1d2ac60ca5…

MALICIOUS

Office (OLE) / .XLS

107.0 KB Created: 2022-09-26 04:46:32 Authoring application: Microsoft Excel First seen: 2022-09-26
MD5: 4d3137651038dfe44ccf6440f6281dfb SHA-1: 2d28e875fca6e4f945b5165b03f9aa7747764836 SHA-256: 13c9bc1d2ac60ca5abb5a235d7d27d8c6f06e497da360f391785044d413cc29e
340 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1218.011 Signed Binary Proxy Execution: Rundll32 T1140 Deobfuscate/Decode Files or Information

The sample contains VBA macros, including an Auto_Open subroutine, which is a common technique for initial execution. Heuristics indicate the use of CreateObject and a reference to certutil, suggesting the download and decoding of a payload. The obfuscated VBA code, including reassembled tokens like 'WScript.Shell', points to the execution of arbitrary commands, likely to download and execute a second-stage payload.

Heuristics 8

  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
  • 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.
  • Reference to certutil (download/decode) high SC_STR_CERTUTIL
    Reference to certutil (download/decode)
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
9341472611735e41842168a3deb7f85c41f091e3096f8399c9850b1e3478870d		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 8341 bytes

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