Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 f7531173cfb1295e…

MALICIOUS

RTF / .DOC

241.5 KB First seen: 2021-09-25
MD5: 455b2612824ea479902e446f2197c2d1 SHA-1: 85b7a71bff95999bade5a2ed373c98d301b79196 SHA-256: f7531173cfb1295eb071081c501ce1c8f3273576edab78ae993a18ce2abc0674
340 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1137.003 Libtool Dynamic Library Modification

The RTF document contains multiple OLE objects, including automatically linked and updated objects, which are designed to activate embedded content. The presence of a 'Macro/content-enable lure' heuristic indicates the document likely instructs the user to enable macros or editing to bypass security measures. This suggests the file is a dropper intended to download and execute a second-stage payload upon user interaction.

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.
  • 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 3 \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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000969.bin rtf-objdata-decoded RTF \objdata at offset 0x969 26658 bytes
SHA-256: d02955434f88e0190958513351ffebd18856b4e92a81f958951cd5fcebb70d8a
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_01_off0000e2a2.bin rtf-objdata-decoded RTF \objdata at offset 0xE2A2 2632 bytes
SHA-256: 9d9bc825f2fa5e0ed8db7dce6823e199ad9c775873472d42887214589f205470
objdata_02_off0000f845.bin rtf-objdata-decoded RTF \objdata at offset 0xF845 12297 bytes
SHA-256: 44deae4627fee3c44f54d5bd10477ec2e17f4c08135f08e2417832e36d10d037