Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 46c85f8e26c04207…

MALICIOUS

RTF / .DOC

4.5 KB First seen: 2022-09-26
MD5: a2f6b3f1ecf049aa61ff686213c7af7e SHA-1: bbb895b4c027f0a1c36487082bd901e60ec70d98 SHA-256: 46c85f8e26c042078bb1a38e521a4be458df3d3a174b3424d07887f9bca7e03f
120 Risk Score

Malware Insights

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

The RTF document contains embedded OLE object data and specifically triggers the Equation Editor vulnerability. The ".objupdate" directive forces the activation of this embedded object, leading to the execution of malicious code. This is a common delivery mechanism for exploiting older Microsoft Office vulnerabilities.

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_off00000078.bin
edccb42465aedbb9d9b5c5f49ddf626db12cbf9c30629aa721f2e4aef86f6ea2
rtf-objdata-decoded RTF \objdata at offset 0x78 1963 bytes