Malicious RTF — malware analysis report

Static analysis result for SHA-256 4d61ac16894b6366…

MALICIOUS

RTF

817.2 KB Authoring application: Riched20 10.0.18362 First seen: 2020-09-24
MD5: ab33b4bb5941fbd1161a3146212ac982 SHA-1: e211ced06422b094eec8c4a30a7013371045d767 SHA-256: 4d61ac16894b63662bb8f904ff95806064d5d072e45730199b8786341507f0de
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple OLE objects, including embedded objects that trigger activation via \objupdate. The presence of a Composite Moniker and OlePres stream strongly suggests an attempt to exploit OLE object handling vulnerabilities for arbitrary code execution. This is a common technique for delivering malicious payloads via email attachments.

Heuristics 5

  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 12 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000fa.bin rtf-objdata-decoded RTF \objdata at offset 0xFA 28008 bytes
SHA-256: c7ac50b0e7aed20957cb8ab991306bffd900f68906ca964ba0f1621be648885e
objdata_01_off00011153.bin rtf-objdata-decoded RTF \objdata at offset 0x11153 28008 bytes
SHA-256: e2b4207b7a649b95aac698a5dd729e732faa2044d3adfb7647a27368c4dbfc93
objdata_07_off00077369.bin rtf-objdata-decoded RTF \objdata at offset 0x77369 28008 bytes
SHA-256: 4cc363877eca71f49d5fa30fa3cc2e25248dca7ce470b9c687ae9cdaa41e829e

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