Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 2af9ffcb95eb7c36…

MALICIOUS

RTF / .DOC

55.5 KB
MD5: 2cc50352cb33f5c8b4b4845044327562 SHA-1: 68c002e6286ee485f50f4bbfb664d06a0f2b83dc SHA-256: 2af9ffcb95eb7c365400be5b84601812703a24c99d4a598653fde25b8813e0fe
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that contains embedded OLE object data and triggers an objupdate event, indicating it attempts to activate the embedded object. The critical heuristic firing for RTF_EQUATION_EDITOR strongly suggests exploitation of a known vulnerability in Microsoft Equation Editor. This technique is commonly used to deliver a second-stage payload.

Heuristics 3

  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001bcb.bin
f7bdf5a2c8bb049127689bbfb7ed52a65c6b6736b118451e0ac471af07923741
rtf-objdata-decoded RTF \objdata at offset 0x1BCB 1762 bytes