Malicious RTF — malware analysis report

Static analysis result for SHA-256 feb19a78f1aa16da…

MALICIOUS

RTF

39.5 KB First seen: 2019-02-10
MD5: e39ec6b9151733d1e9b703d84f279288 SHA-1: c473251b07e58fa7f5607ee4d660e75f5ebab552 SHA-256: feb19a78f1aa16da05b2cdcc165821e80a718d755e2ea26c4a399bc7a4616aef
240 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data and specifically triggers the CVE-2017-11882 vulnerability via an Equation Editor font record overflow. This exploit allows for arbitrary code execution, likely to download and run a secondary payload. The presence of the Equation Editor CLSID and the specific CVE firing strongly indicate this attack vector.

Heuristics 5

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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 13096 bytes
SHA-256: 9d9a0500f2f802c3ed8261f3ca74026d4e55dd4ce06691947ede2dacf4872c71

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