Malicious RTF — malware analysis report

Static analysis result for SHA-256 fff895c58b4d25e9…

MALICIOUS

RTF

223.4 KB First seen: 2021-01-15
MD5: 54f98e6bb5bb875a0cc53c45afc04b09 SHA-1: 11a86bfde0c1c20e6434ab33b6c7547387229b9e SHA-256: fff895c58b4d25e918771bba722a1e83e349363b0937471d7ba1f14aa987dd93
320 Risk Score

Heuristics 9

  • 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-2017-0199 / CVE-2017-8759 (OLE2Link auto-activated remote loader) critical CVE related RTF_OLE2LINK_REMOTE_MONIKER_LOADER
    RTF embeds an OLE2Link object that is force-activated with \objupdate (no user interaction on open) and fetches a remote second stage — through an INCLUDETEXT/INCLUDEPICTURE field or the OLE object's own moniker. This is the OLE2Link auto-update attack path shared by CVE-2017-0199 (server returns an HTA/scriptlet) and CVE-2017-8759 (server returns a SOAP WSDL the .NET parser compiles). Office processes the fetched response through the same code path; the specific CVE depends on the now-unreachable server content type.
  • 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.
  • 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
  • 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.
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000531e.bin rtf-objdata-decoded RTF \objdata at offset 0x531E 9072 bytes
SHA-256: 1cfc1ed36778b158db4be1a279b893a53c658825c560d2bc2c207c338198b567
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Sh"
objdata_01_off00009b03.bin rtf-objdata-decoded RTF \objdata at offset 0x9B03 12261 bytes
SHA-256: 010714f1a05164de42b9cf9db473155bac2155f3569c1db08838e973f2cd6269
objdata_02_off0000fb15.bin rtf-objdata-decoded RTF \objdata at offset 0xFB15 2632 bytes
SHA-256: cd422fad722349d22695a105a39c207bb6dc345f5ecfd1a9b29a77859048a591