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

Static analysis result for SHA-256 33ec287ca5f16134…

MALICIOUS

Office (OLE) / .XLS

143.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 13911a3360b3c163e01afaa92dbc0ec7 SHA-1: b2358d9434701f7efac01fd57df2a9d660a633d2 SHA-256: 33ec287ca5f16134d2cb59e22fb694005af28fe110eb303d109d94b874b539d5
180 Risk Score

Malware Insights

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

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The document body displays a deceptive message to encourage users to enable content, which would trigger the macro execution. The macro uses dangerous APIs and environment evasion techniques.

Heuristics 4

  • 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.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
79e3cee210d356363fb155b3b4e25cd9344ed95c5e5a8e449660c7ccc499b3ec
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 172299 bytes