Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 795da58639023372…

MALICIOUS

RTF / .DOC

3.9 KB First seen: 2022-05-16
MD5: ae9e458d8f85020fb71906c1e7434b95 SHA-1: 14f0fdb069bf0b89d7a4614b8fb54d0581cbf9a3 SHA-256: 795da586390233720c1220d563439b17af5bb1c02cfdb030dfc12898a98f34ff
121 Risk Score

Malware Insights

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

The file is an RTF document containing embedded OLE object data, specifically targeting the Equation Editor vulnerability. The \objupdate directive forces the activation of this embedded object, leading to arbitrary code execution. This is a common delivery mechanism for exploits targeting older Microsoft Office versions.

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_off000000a5.bin
2f66b848cf1428e29c602446f7513ed7e3f8a4c8c5a37d6d41783d98f812fb39
rtf-objdata-decoded RTF \objdata at offset 0xA5 1672 bytes