Malicious RTF — malware analysis report

Static analysis result for SHA-256 99350c05688218f9…

MALICIOUS

RTF

445.4 KB First seen: 2019-05-16
MD5: edfffa2a1973e85f6ebc6836c5fd7d57 SHA-1: 69cc8ede8fb65447b635606a60c1fc7e91821bca SHA-256: 99350c05688218f92699b540f88b39ea8c6360136713d21f5615377583ef4f61
140 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object, specifically triggering the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is known to allow for arbitrary code execution, which is typically used to download and run a second-stage malicious payload. No document body text or scripts were extracted, but the critical heuristic firing strongly indicates exploitation.

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.
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000014b5.bin rtf-objdata-decoded RTF \objdata at offset 0x14B5 3628 bytes
SHA-256: a74fe51c281c518abe31aa06a1cb55fbb510ef181767a6b5163e5d331801c6b0

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