Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ff381561194eae8d…

MALICIOUS

RTF / .DOC

295.5 KB First seen: 2021-05-04
MD5: 56031cae7ff0acf6da4b77070c607774 SHA-1: c9f9047e53d83becc7c6076c899a703f1e6e1a76 SHA-256: ff381561194eae8d503307490082530d0b452297e33610d219d6a116814b6447
340 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1566.001 Phishing: Spearphishing Attachment

The RTF document contains multiple OLE object data sections and uses automatic linking and update triggers, indicating an attempt to embed and execute external content. The document body explicitly instructs the user to 'download the document and click Enable Editing', a clear lure to bypass macro security. This suggests the file is a dropper designed to execute malicious code 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 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
🗂 Part of campaign: shared payload 3cd3b7d42e 51 samples

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000096e.bin rtf-objdata-decoded RTF \objdata at offset 0x96E 40496 bytes
SHA-256: b86285cf85473033421eaa6ac087d29112ec12423be5d63b0ca2c2879af6766e
objdata_01_off0000711d.bin rtf-objdata-decoded RTF \objdata at offset 0x711D 40469 bytes
SHA-256: 1e288fdbcba32bcb5b32713c99f4737bfb6bce263f9838697249840249cb94de
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off0001ba8e.bin rtf-objdata-decoded RTF \objdata at offset 0x1BA8E 2632 bytes
SHA-256: 3cd3b7d42e5855c90d6d11c54ef2670ed8970441480cc23f7d39ef08fa1c935b
objdata_03_off0001d031.bin rtf-objdata-decoded RTF \objdata at offset 0x1D031 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7