Malicious RTF — malware analysis report

Static analysis result for SHA-256 4e242ba808f8bdc8…

MALICIOUS

RTF

8.2 KB First seen: 2019-01-25
MD5: fb96e605f934d07873cba8f6fbd4f674 SHA-1: 1269f6e51f20d90a456b42a44afac34cee6cbeb1 SHA-256: 4e242ba808f8bdc82b4bf7b35f82586d66ab6291bb8214136c1b36c7f32675e5
240 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. 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 FONT record overflow signature strongly indicate this exploit.

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_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4153 bytes
SHA-256: 6ae0d628d767e697fc018cdf61131dbdc503b2dbb3298c78b0876ad0c8b4223c