Malicious RTF — malware analysis report

Static analysis result for SHA-256 f3af528709d11ea4…

MALICIOUS

RTF

261.1 KB Created: 2018-07-03 09:28:00 First seen: 2020-02-04
MD5: 436bc5cc20f4cacac6761c7b57a28c1b SHA-1: 66b74f5f509f07ba16c0a65e7f52c4a3d9bb803e SHA-256: f3af528709d11ea400103eaceb0682ed29e25cb9d9b00ff34200050c68e15baa
262 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects and exploits known vulnerabilities, specifically CVE-2017-11882 (Equation Editor FONT record overflow) and CVE-2017-8759 (MSXML SAX OLE activation). These exploits are designed to execute arbitrary code, likely to download and install the MSI payload from the suspicious URL http://houwelyckx.be/backups/cgi/mviave.msi. The ClamAV detection further confirms the malicious nature of the file.

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://houwelyckx.be/backups/cgi/mviave.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: 8ce31a77df0064a2decc65f1b5737c3dcb08731b54bed5f8973937fd6a51c1b4

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