Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d5a42cf5f5861024…

MALICIOUS

RTF / .DOC

634.4 KB
MD5: 76321ea5f8952b64d3530961f319af28 SHA-1: 7a907fe0eaea5850d95800236792409ad24e7bcc SHA-256: d5a42cf5f5861024aac11d2f58f174aa8a35b20b33a410a7d60c79f9f5744398
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability within the Equation Editor OLE object. This exploit is designed to execute a decoded PE file, which is likely a secondary payload. The high entropy of the decoded object and the presence of OLE object data strongly indicate a malicious intent to achieve arbitrary code execution.

Heuristics 6

  • 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.
  • 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
  • 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_off00000047.bin
6ea43f5d4174b3c11c0be81cf43fddb4bbe0c9c2199b3d7512411da4892ebd58
rtf-objdata-decoded RTF \objdata at offset 0x47 324689 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.