RTF / .DOC malware analysis — malicious · 908c453c55ba0233

MALICIOUS

RTF / .DOC

1.90 MB First seen: 2022-04-20

MD5: 13442e8da596e65b36599456ad02835e SHA-1: 1ab28f845c79f3639a8b0c2760055bf3a3dedcb8 SHA-256: 908c453c55ba0233482766db5b7d7e15eefeaac8acbcb2cd2c2705f7cedb5c0f

260 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204 User Execution

The RTF file contains multiple critical heuristic firings indicating the exploitation of CVE-2017-11882 via an embedded OLE object. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_RELATED` strongly suggests this vulnerability is being leveraged. The large amount of hex-encoded data within the OLE object (`RTF_EXCESSIVE_HEX`) likely hides the secondary payload. No document body text or scripts were extracted, but the exploit itself is sufficient to infer a malicious intent to execute arbitrary code.

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

RTF contains ~1979KB 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00001dce.bin` `256bc4a482f734005b5085de90343bd37b78c33e7c61310a2035ef17a543e26c`	rtf-objdata-decoded	RTF \objdata at offset 0x1DCE	989755 bytes

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