Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 079b1d4256bff9e2…

MALICIOUS

RTF / .DOC

27.8 KB
MD5: 07306ff58a2e4461a16a8e073cf5efe9 SHA-1: c1a37def838bcddada0eff4ea244c9d05e3fd577 SHA-256: 079b1d4256bff9e20443e84f6cf3c2105904fed8d717eaab9ffe106b03cd5c56
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The ".objupdate" directive forces the activation of this embedded object, leading to arbitrary code execution. This is a common technique for delivering malicious payloads via email attachments.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000011cc.bin
31819ecd20860c2cc69dc9d77b0b1f99d1fd9a3b481b4189ec5cfccc72cf903e
rtf-objdata-decoded RTF \objdata at offset 0x11CC 1474 bytes