Malicious RTF — malware analysis report

Static analysis result for SHA-256 93c675c9b730f93d…

MALICIOUS

RTF

5.62 MB Created: 2021-10-27 18:20:00 First seen: 2021-11-24
MD5: b93af307f3c4ec123b9ffe8125604157 SHA-1: 11aa6ebc403afb44a647351ba4dbb8a06b8d479f SHA-256: 93c675c9b730f93df56e5e242b0cf210a5640da9de2b662639e8adc9217c29f2
362 Risk Score

Malware Insights

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

The RTF file contains multiple critical heuristic firings indicating exploitation of CVE-2017-8570, CVE-2017-8759, and CVE-2026-21514. These vulnerabilities allow for the execution of arbitrary code, likely to download and run a secondary payload. The presence of OLE object data and composite monikers further supports the exploitation of these vulnerabilities for initial execution.

Heuristics 10

  • 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.
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • 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.
  • CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514
    RTF contains a hidden \svb hex package with DrsE2oDoc and downRevStg drawing compatibility parts. This matches an observed CVE-2026-21514 exploitation shape that manipulates Word's internal document structure and trust decisions.
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1651KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00540dff.bin rtf-objdata-decoded RTF \objdata at offset 0x540DFF 96076 bytes
SHA-256: cd6eb1e1caeb93327ff7d83d81098a9a3719c4806a6c1e453339037a78fd4e44
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_01_off00571b3a.bin rtf-objdata-decoded RTF \objdata at offset 0x571B3A 2632 bytes
SHA-256: ad7bf1923f855fca5949d0c557a2a819b106cd84b204870bcc59064eb0c6e331
objdata_02_off005730dd.bin rtf-objdata-decoded RTF \objdata at offset 0x5730DD 12297 bytes
SHA-256: 44deae4627fee3c44f54d5bd10477ec2e17f4c08135f08e2417832e36d10d037
rtf_svb_00004896.zip rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x4896 819490 bytes
SHA-256: 24a53a09dd578ae9726b4a2c5f1f2f62fcce17cc0dd17d3ba3b092212bc43d09