Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 28f477129ed9301d…

MALICIOUS

RTF / .DOC

333.2 KB
MD5: 657f33c1f20ba839039d7998f7e58fc8 SHA-1: 488cdb9d1f88fe184f7d0924499838d0f01dfba4 SHA-256: 28f477129ed9301d972a5dc7c6dbd9a74f319762bd6ee840662d1f88d91bb512
122 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that decodes to a PE file, indicating a likely exploit targeting the Equation Editor. The presence of ".\objupdate" suggests that the OLE object is activated automatically upon opening the document, leading to the execution of the embedded payload. This is a common delivery mechanism for malware.

Heuristics 4

  • 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_off0000006f.bin
0c1e092c345af2c8194cf3ce82a2a4cd8ba76fd2ab21ce23ccf18456fed85eab
rtf-objdata-decoded RTF \objdata at offset 0x6F 170439 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.