Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 30fb07f3d0ff5583…

MALICIOUS

RTF / .DOC

11.6 KB First seen: 2022-02-24
MD5: c13fb5c2889ecf291ba719fa5e598a8d SHA-1: df34705ab05381172150afa03f04ca090427f7f5 SHA-256: 30fb07f3d0ff5583e496de2b238d75ef42ced2f66d9f9459e3f26ee87c5d85ce
121 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, specifically targeting the Equation Editor vulnerability. The \objupdate directive indicates that the embedded object will be activated automatically upon opening the document. This exploit is commonly used to download and execute a second-stage payload. No specific family could be identified, but the attack pattern is consistent with known exploit documents.

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_off00001e10.bin
4ae935f511df6785216d00536393d2ad042d9d9591e0ff7fd0fbe6223f4a6ca5
rtf-objdata-decoded RTF \objdata at offset 0x1E10 1895 bytes