RTF / .DOC malware analysis — malicious · c99792ac09f1aa37

MALICIOUS

RTF / .DOC

1.20 MB First seen: 2022-10-17

MD5: e3e31912fbd4565a367ea9b5ab98f12a SHA-1: 44ee7e427600e1a67783c0483885bebede1e0d8e SHA-256: c99792ac09f1aa379a8640fde68ad4fbbb6c43b5bf5e24b88f0ac29f3ead346d

222 Risk Score

Malware Insights

MITRE ATT&CK

T1204.002 Malicious File T1559.001 Component Object Model

The RTF document contains an OLE object with decoded Equation Editor payload, strongly indicating exploitation of CVE-2017-11882. The presence of a large, high-entropy embedded artifact suggests it is a packed or obfuscated second-stage payload. The file's SHA256 hash is included as a primary IOC.

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.
\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.
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~1256KB of hex-encoded data inside \objdata sections — may hide a payload
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_off0000007a.bin` `81bf2a3304d4b87bce2b8a31b522fcecd55b01f1ea72b8b726cbdae1ef20cd69`	rtf-objdata-decoded	RTF \objdata at offset 0x7A	628385 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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