RTF / .DOC malware analysis — malicious · b78a76ff52dd90cc

MALICIOUS

RTF / .DOC

631.2 KB

MD5: 3f5abfd2c776f9e863553c024d207b3a SHA-1: b340ac80320cf5dc8a6e1805742e82c6f6a4d141 SHA-256: b78a76ff52dd90cc1b89400b9404f2f1fe973c62796fc049ebdb83348239ecde

222 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in the Microsoft Equation Editor. This vulnerability allows for the embedded OLE object to be automatically activated and executed. The decoded object contains a PE file, indicating that the exploit is used to drop and execute a secondary malicious payload. The specific family is not identifiable from the provided heuristics.

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.

Filename	Kind	Source	Size
`objdata_00_off00000047.bin` `326dcf21b03491c3e2d99de3927f50d6a3cc799827de2d7c481ddfa0a47cbd59`	rtf-objdata-decoded	RTF \objdata at offset 0x47	323102 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.

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