Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 28d6be8cd812077d…

MALICIOUS

RTF / .DOC

4.5 KB First seen: 2022-08-16
MD5: 1a41fa1f3a1e1641c20024fb5fb7affe SHA-1: 3274f32bb8d26e823941f27e0fa0f7decc20a410 SHA-256: 28d6be8cd812077d74c15f674f0506d58fc08b19829be0db2738712acc124c67
120 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) via embedded OLE object data. The \objupdate directive forces the activation of this embedded object, leading to code execution. This is a common technique for delivering secondary payloads, though no specific payload was identified in this analysis.

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_off000000b8.bin
a400715eacaffbe94f274b1a739f2bbd8eaf12db5322beb8656d712e22dc8a54
rtf-objdata-decoded RTF \objdata at offset 0xB8 1907 bytes