Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 84f073c7f41a06f8…

MALICIOUS

RTF / .DOC

68.6 KB
MD5: bbe32e540d3697c7ce6c081106f16d06 SHA-1: b9743a08bc7b9123cc3e7e03a48035c2f0ff7e77 SHA-256: 84f073c7f41a06f83ec723ba114096d67c5e86b2b75999b9c1ff3e9763528718
182 Risk Score

Malware Insights

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

The sample is an RTF document that contains a decoded Equation Editor payload, indicating exploitation of CVE-2017-11882. This vulnerability is used to execute a secondary payload, likely a PE file, which was carved out as 'objdata_00_off00000f0e.bin'. The presence of ".bin" in the extracted artifact name suggests a potential executable payload.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Decoded Equation Editor payload + PE critical RTF_EQUATION_EDITOR
    RTF decodes to an Equation Editor ProgID adjacent to OLE activation and the same decoded object stream contains embedded PE bytes. This matches the Equation Editor exploit surface used by CVE-2017-11882 / CVE-2018-0802 documents, while requiring payload evidence to avoid flagging benign Equation references.
  • \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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000f0e.bin
d329d4421328e2cec29ac065530bb55c8d390df04e51dece4252af548948f6e8
rtf-objdata-decoded RTF \objdata at offset 0xF0E 32864 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.