Malicious RTF — malware analysis report

Static analysis result for SHA-256 497a2a8e932f715e…

MALICIOUS

RTF

9.1 KB First seen: 2019-05-31
MD5: e908a8f32e8d24ef81fd93a661184094 SHA-1: f46c81f366eb87dafafef010fcda2d6c4ec26aae SHA-256: 497a2a8e932f715e612996408ac1249df957f73b75328c685c7dc10f3a37e7f1
240 Risk Score

Malware Insights

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

The sample is an RTF document containing embedded OLE object data. Heuristics indicate a critical vulnerability in Equation Editor (CVE-2017-11882) is being exploited, which allows for arbitrary code execution. The presence of ".objupdate" further suggests an attempt to force OLE activation. This exploit is commonly delivered via spearphishing attachments.

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 4649 bytes
SHA-256: 21d8ddc228c8eaeb5a7b3deb2249a666fc941128317b988946f3fc6bb230f4cf