Malicious RTF — malware analysis report

Static analysis result for SHA-256 bd642cba69573c23…

MALICIOUS

RTF

519.1 KB First seen: 2019-04-17
MD5: ee4d5dc98744e348344aa2da9b556dc5 SHA-1: d47caaa2e2a964c12fb6aeda07924ff8dacfd6a3 SHA-256: bd642cba69573c23661487ec4bece0e898372809ed8a585d856706ba025dc1fe
220 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and triggers heuristics indicating the exploitation of CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This exploit is commonly used to achieve arbitrary code execution, typically to download and run a second-stage malicious payload. The ClamAV detection further confirms the malicious nature of the file, specifically identifying it as an exploit targeting this CVE.

Heuristics 5

  • 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
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off000008fe.bin rtf-objdata-decoded RTF \objdata at offset 0x8FE 4146 bytes
SHA-256: 9d08c0145d9dd71f0cb46524b77e88c9adf8125a50b2209aeee98d5dfa0c79b7