Malicious RTF — malware analysis report

Static analysis result for SHA-256 c75ea5ad2b02cf15…

MALICIOUS

RTF

16.9 KB First seen: 2018-10-19
MD5: 1f30cde571256ec8c7889740891d578f SHA-1: 50478d2bb52ba53ad8dc08471e9b559f400cae7b SHA-256: c75ea5ad2b02cf151ee68626f868a7c62fce5611c67c417c41c18f9c09b9172d
200 Risk Score

Malware Insights

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

The RTF file contains an OLE object that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability is commonly exploited to execute arbitrary code, likely to download and run a second-stage 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_off00000cd9.bin rtf-objdata-decoded RTF \objdata at offset 0xCD9 4655 bytes
SHA-256: b825a1c48399bc05727806dbd126a69f8bc60ee70270f257af79808c2ca46552