Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fc5c1044523a10a3…

MALICIOUS

RTF / .DOC

340.5 KB
MD5: 7b300ad981bd98b367d5800d3b84e3c4 SHA-1: d185b28d1feacbe32302994d94d10cc11d3e5dc9 SHA-256: fc5c1044523a10a3f2b91b543e36e0ce067dd80eb8e1cea82722f575f1fa5546
182 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains an embedded OLE object with a ProgID indicative of Equation Editor, triggering critical heuristics for CVE-2017-11882. The ".objupdate" directive forces OLE activation, leading to the execution of the embedded payload. The high entropy and MZ offset of the decoded OLE object suggest it is a packed executable. The primary attack vector is likely a malicious attachment delivered via spearphishing.

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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \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
  • 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_off000010c0.bin
cb39a18d478cfc8ac71be790d4d1b756c35e1565afd382539d9f248590616e47
rtf-objdata-decoded RTF \objdata at offset 0x10C0 171971 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.