Malicious RTF — malware analysis report

Static analysis result for SHA-256 d64928fe1a1b6b9e…

MALICIOUS

RTF

359.6 KB First seen: 2021-05-23
MD5: a6c22c66185350cc1d9d32a026bd2767 SHA-1: 8d2c1479a41f1a07c4e073bbffc92c8fa24c92bf SHA-256: d64928fe1a1b6b9e3043f4d567da092f9a4a4a3eb4c7541bb49d6ef456a874f0
280 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of malicious OLE object embedding and automatic linking, specifically related to CVE-2017-8570. The document body explicitly instructs the user to 'download the document and click Enable Editing', which is a common lure to bypass security measures. The presence of shellcode command strings and extracted artifacts like 'objdata_01_off00007114.bin' suggests that the file is designed to execute a secondary payload.

Heuristics 8

  • Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570
    RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • OLE object data medium RTF_OBJDATA
    RTF contains 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000965.bin rtf-objdata-decoded RTF \objdata at offset 0x965 72049 bytes
SHA-256: 3cd8f5dc64b684bbc6f001942fd211c8235fe91402da45c28aaa66f3ce90cebf
objdata_01_off00007114.bin rtf-objdata-decoded RTF \objdata at offset 0x7114 72022 bytes
SHA-256: 2f4f7ec930f92567f0640bb0c97040bd4f196c50d0c20ad3ec6775d2df67807e
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off0002bae3.bin rtf-objdata-decoded RTF \objdata at offset 0x2BAE3 2632 bytes
SHA-256: 1168a119c26543fbaa6e9ad1f2c0221f803fb28859c4a42b2857ff6b316de929
objdata_03_off0002d086.bin rtf-objdata-decoded RTF \objdata at offset 0x2D086 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7