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

Static analysis result for SHA-256 871630da02f1196f…

MALICIOUS

Office (OLE) / .XLS

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-03
MD5: 055260545498031c38bfe0c75f0b6545 SHA-1: 59a5a5b1da4aadb60cce918559e6b2e2d663dd81 SHA-256: 871630da02f1196f85572e268a602f8b3699072f2f79b1b5cb00f46406805128
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Control T1059.001 PowerShell T1204.002 Malicious File: User Execution

The file contains Excel 4.0 macros, specifically an Auto_Open macro that utilizes dangerous formula APIs such as RUN. This indicates an attempt to automatically execute code upon opening the document. The extracted URLs are likely used to download and execute a second-stage payload. The presence of the RUN function in the Auto_Open macro is a critical indicator of malicious intent.

Heuristics 3

  • 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.
  • 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
b2124f09a0fec7faeef42f88c68da164b6a9b84efed16f528c7ac11c7695b4b9
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7646 bytes