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

Static analysis result for SHA-256 6e6be573ffc82e1f…

MALICIOUS

Office (OLE) / .XLS

599.0 KB Created: 2021-06-07 14:00:00 Authoring application: Microsoft Excel
MD5: 1d6c0697403130de849d63ea62b05831 SHA-1: 1294574bbd916549971f96fa48fc2bcaaef58b0c SHA-256: 6e6be573ffc82e1ff623948f4b7a7a57d891892ffd1f547399aef02cbde3763f
480 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

This Excel file contains heavily obfuscated VBA macros, including an Auto_Open function designed to execute malicious code. The macros utilize `CreateObject` and `Shell()` calls, indicative of downloading and executing a second-stage payload. The heuristic 'OLE_VBA_SPLIT_KEYWORD_OBFUSCATION' specifically flags the reassembly of 'Scripting.FileSystemObject', a common technique for evading static analysis. The presence of 'SE_PASSWORD_ARCHIVE_LURE' suggests a social engineering tactic to trick the user into providing a password for an archive, likely containing the actual malware.

Heuristics 11

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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.
  • 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.
  • ClamAV: Xls.Malware.Valyria-6995973-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-6995973-0
  • Heap-spray pattern detected high SC_HEAP_SPRAY
    Repeated 0x41 (A) bytes found
  • 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.
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • NOP-equivalent sled detected medium SC_NOP_EQUIV_SLED
    Long run of 0x41 bytes
  • 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
89769c91a19615c7e22be5d0f6a421adddd8100e5ec1e825fa131ddcc5cddaf4		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2503 bytes

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