RTF / .DOC malware analysis — malicious · cabcec0d5650ad72

MALICIOUS

RTF / .DOC

3.91 MB First seen: 2022-05-23

MD5: 86e3ed9e405fffcae6fe645d3ff9a255 SHA-1: b4dea46e1efb79e3955727a5bf6b3dc1b898b7c1 SHA-256: cabcec0d5650ad72d458d81447f942082a9af4272c73c12d121ad1e136545b39

382 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell T1105 Ingress Tool Transfer

The RTF document contains multiple indicators of exploitation for CVE-2017-11882, including OLE object data, Equation Editor ProgID, and an embedded PE header within hex data. The presence of ".bin" files extracted from the objdata sections suggests the RTF is acting as a dropper for a secondary payload. The ClamAV detection of Rtf.Dropper.Agent-9965975-1 further supports this assessment.

Heuristics 10

Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED

RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED

RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR

RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
PE header (with DOS stub) in hex data critical RTF_MZ_HEX

Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
\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 ~2001KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 2 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object
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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000012b8.bin` `30b98f06c41c35c2e33653d6f02d0495930a2d85f652e7290f7439571cd1e1a8`	rtf-objdata-decoded	RTF \objdata at offset 0x12B8	1032492 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.79, consistent with packed or encrypted content.
`objdata_01_off0020d1b3.bin` `b5fb24d310a9bf9f48aea8e381ad105e2f4a64fcacf54516332e6d3acbd8cb23`	rtf-objdata-decoded	RTF \objdata at offset 0x20D1B3	462306 bytes

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