Malicious RTF — malware analysis report

Static analysis result for SHA-256 bfc1764d3cc1d4f6…

MALICIOUS

RTF

19.3 KB First seen: 2018-09-04
MD5: 926aaf454c51e0d110d7de5eadb6afb9 SHA-1: 87c14ef411b5ba1c80ca3fbdf289345d9dd475a0 SHA-256: bfc1764d3cc1d4f6c8592e272d9eafd7e2c522111bafd0a89337bf6030190ead
200 Risk Score

Malware Insights

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

The RTF document contains an OLE object that leverages the CVE-2017-11882 vulnerability in the Equation Editor. This vulnerability is known to be used for arbitrary code execution, likely to download and execute a second-stage payload. The presence of the ".bin" file in the embedded artifacts further supports the delivery of a malicious payload.

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_off00001679.bin rtf-objdata-decoded RTF \objdata at offset 0x1679 4658 bytes
SHA-256: 407e993d3ca07fc21473ee35a37e7a8eb99bdf432aa15b3981f5deeae7251041