Malicious RTF — malware analysis report

Static analysis result for SHA-256 d9a528d047b503ff…

MALICIOUS

RTF

8.2 KB First seen: 2019-05-31
MD5: 97b03e76c9a885d3b00fd7d376993551 SHA-1: ac408750a19ef118ed8cc7a585dd6d6fa3d98463 SHA-256: d9a528d047b503ff551ceeb54d841981e948c91f61c0db4b264d6ceee1b6d20c
260 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. Critical heuristics indicate the exploitation of CVE-2017-11882 via the Equation Editor component. This vulnerability allows for arbitrary code execution when the document is opened, likely delivered via spearphishing.

Heuristics 6

  • 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
  • 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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4148 bytes
SHA-256: 498b5e24b03e3880c3f947f8792e62a10835d36e1fd78adee342e6b2ff90a9b0