Malicious RTF — malware analysis report

Static analysis result for SHA-256 862400f8d31c7038…

MALICIOUS

RTF

25.6 KB First seen: 2023-05-26
MD5: 211091ff25b68364c7973844af7a44d4 SHA-1: 59be02fe2336f48b74fc0ec9cb59661655707c06 SHA-256: 862400f8d31c7038f3a68b6a21c51a859dba79c46f1a645f793cbc1edf4420eb
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The RTF document contains an OLE object that leverages the CVE-2017-11882 Equation Editor vulnerability. This technique is commonly used to execute arbitrary code, likely to download and run a secondary payload. The presence of the Ole10Native stream and objdata further confirms the exploitation attempt.

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_off0000120b.bin
ea1f8819a8dbeef62c77bcb9afc6c62df1afaf4a2ed57780bf918ee6c056732a
rtf-objdata-decoded RTF \objdata at offset 0x120B 4176 bytes