Malicious RTF — malware analysis report

Static analysis result for SHA-256 22c47a0c7ce87b13…

MALICIOUS

RTF

261.1 KB Created: 2018-07-03 09:28:00 First seen: 2019-04-21
MD5: 96860ced7cf1383245ef6838129293a0 SHA-1: 187e5cc178e724a465a679cf97f4653ca8465127 SHA-256: 22c47a0c7ce87b135685df305e7d30e7258a36f7f580de0114e361581cc54f54
262 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects and triggers critical vulnerabilities CVE-2017-11882 and CVE-2017-8759. These exploits are commonly used to execute arbitrary code, likely to download and run a secondary payload from the unknown URL http://bangbor.go.th/image_files/img64.msi. The file is identified as malicious by ClamAV with a specific detection for CVE-2017-11882.

Heuristics 7

  • 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.
  • ClamAV: Doc.Exploit.Cve_2017_11882-7570663-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.Cve_2017_11882-7570663-1
  • \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://bangbor.go.th/image_files/img64.msi In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000bf6b.bin rtf-objdata-decoded RTF \objdata at offset 0xBF6B 15672 bytes
SHA-256: caa67fafc6da25833e4ffa2e091fc52ab915d3eb328eb28483c8c1f7f68dee7c