Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 38f72fa8a8971d3d…

MALICIOUS

RTF / .DOC

25.8 KB First seen: 2022-08-31
MD5: 73382d3c097e123909042b54d40bacf1 SHA-1: 8c5b4409aadd44c8996099897bb9939d0f3ccb4d SHA-256: 38f72fa8a8971d3d938b57a27f192adfd3fbb3062f81b0f7a082e77fd81b11be
200 Risk Score

Malware Insights

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

The sample is an RTF document containing embedded OLE objects, specifically triggering heuristics related to CVE-2017-11882 and Equation Editor exploitation. The presence of ` objdata` and ` objupdate` directives indicates that the embedded OLE object is designed to be activated automatically, likely leading to the execution of a malicious payload. The high entropy of the decoded OLE object further suggests it contains packed or encrypted data.

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 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001805.bin
2429d787cb4de55cabeb8f4a9fe87362315cfa91d6a39aade1fd4e5468f7e6b8
rtf-objdata-decoded RTF \objdata at offset 0x1805 4328 bytes