Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8ac32b7faa79aabd…

MALICIOUS

RTF / .DOC

295.5 KB First seen: 2021-05-04
MD5: 452e11d23c80550a45b6a498bac85733 SHA-1: 1b1355594eecbfad9803e771bedefedf96ecceee SHA-256: 8ac32b7faa79aabd51156f6503e624a53ee5d355d602784273376ad45e7dbdbf
340 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The RTF document contains multiple OLE object embeddings and auto-linking, with an explicit instruction to 'Enable Editing'. This strongly suggests a lure to bypass macro security settings and execute embedded malicious content. The document body's garbled text and the 'Microsoft Office does not work in email Preview' message are consistent with a social engineering tactic to trick users into opening the file and enabling macros. No specific family could be identified, but the technique is common for macro-based downloaders.

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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

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: b600c83caba658e48b700b42452354b502d5b9403da22e82e8272dbd9e2b026c
objdata_01_off0000711d.bin rtf-objdata-decoded RTF \objdata at offset 0x711D 40469 bytes
SHA-256: b3ba4afc247224262757161bba6cd77f5979d9a488a97b22ae283ced1a9043c5
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

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