Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5e899bdbe6a18d14…

MALICIOUS

RTF / .DOC

928.1 KB
MD5: ed8b3d0b9824d870e3df8e0c34a1798d SHA-1: 5dfe4106139b6cf23005b0d14e353fd712d6a258 SHA-256: 5e899bdbe6a18d146e7d467c32fd230410a29d6ce4177c7d82dde8fd4ea27f81
182 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for the execution of arbitrary code, which is likely used to download and execute a second-stage payload. The presence of the ".bin" file and the specific CVE strongly indicate a malicious intent.

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_off0000051d.bin
98a347894c2ac5d64d2228f26bff28aebda8549500c4c7b88abb5155355fca76
rtf-objdata-decoded RTF \objdata at offset 0x51D 474502 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.