Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 81a138af71728fea…

MALICIOUS

RTF / .DOC

26.1 KB First seen: 2023-07-21
MD5: 1e2437d520b6cf1964cd8146261ab344 SHA-1: 0273ee9d018d450221983a76667b8198f7d8d9f1 SHA-256: 81a138af71728feaf50f380ec7b1d46f9420396e0ca5017e296625a3d5204f2e
200 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for the execution of arbitrary code when the object is activated, likely leading to the download and execution of a secondary malicious payload. The presence of the Ole10Native stream and the specific root CLSID are strong indicators of this exploit.

Heuristics 5

  • Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
  • Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM
    RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001d36.bin
b28f832556775adaa55684dc2b8d21b63012073852d1e93f8e89fed387459da4		 rtf-objdata-decoded RTF \objdata at offset 0x1D36 4174 bytes

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