Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7872305aab420a75…

MALICIOUS

RTF / .DOC

2.07 MB Created: 2012-12-15 15:03:00 Authoring application: LibreOffice/7.1.2.2$Linux_X86_64 LibreOffice_project/8a45595d069ef5570103caea1b71cc9d82b2aae4 First seen: 2021-05-04
MD5: 144b195bfa3deea54e133c06eb308816 SHA-1: 0d3eeacd8a1a76fbc98a4d4cfc7d1436cc58a75d SHA-256: 7872305aab420a758b74bad9b7aa6d81fdc40cf3f5b744edcdc643da94296a2b
360 Risk Score

Malware Insights

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

The RTF document contains multiple OLE objects, including composite and automatically linked objects, which are indicative of exploitation attempts. Specifically, heuristics identify CVE-2017-8570 and CVE-2017-0199/CVE-2017-8759, suggesting the file is designed to drop and execute a script or payload. The presence of large hex data blocks further supports the likelihood of a hidden payload. The document body appears to be a proforma invoice, a common lure for phishing or social engineering attacks.

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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1822KB 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 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
🗂 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_off001c8e87.bin rtf-objdata-decoded RTF \objdata at offset 0x1C8E87 38988 bytes
SHA-256: 919751910456273faec7a81e0ed696e9fc722299ac80988f748281955b44d07b
objdata_01_off001cf636.bin rtf-objdata-decoded RTF \objdata at offset 0x1CF636 38961 bytes
SHA-256: b4914d675bdcc4891272f2bf4945b461568f33c8003aa6895aa9fa8bec645cfb
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off001e3365.bin rtf-objdata-decoded RTF \objdata at offset 0x1E3365 2632 bytes
SHA-256: 3cd3b7d42e5855c90d6d11c54ef2670ed8970441480cc23f7d39ef08fa1c935b
objdata_03_off001e4908.bin rtf-objdata-decoded RTF \objdata at offset 0x1E4908 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7

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