Malicious RTF — malware analysis report

Static analysis result for SHA-256 c991b27d9c738569…

MALICIOUS

RTF

67.6 KB First seen: 2018-11-20
MD5: 5347d1ef12dc3e6438203ea01bffc1bb SHA-1: 73880c42f4fc40d9fb5a96fefd9fc54fe50fc6a2 SHA-256: c991b27d9c7385694235bff19f04afb23e0a68032f03ca2c17016329b9e8d3dd
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains embedded OLE object data and triggers an ".objupdate" call, indicating an attempt to activate embedded objects. Crucially, it fires critical heuristics for CVE-2017-11882, a known vulnerability in Microsoft Equation Editor that allows for arbitrary code execution when exploited via a FONT record overflow. This strongly suggests the file's purpose is to exploit this vulnerability.

Heuristics 4

  • 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.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 4139 bytes
SHA-256: eae7592d6a27a9cf1f7f7b36b731a7d0ed0c09a85377c22073204da1ff55030a

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