RTF / .DOC malware analysis — malicious · 89d730831dc7d8c0

MALICIOUS

RTF / .DOC

1.64 MB First seen: 2022-02-24

MD5: c6b55600442ac7650d1284926160465a SHA-1: c8b122099985a972cc70d515dac549b2695ea976 SHA-256: 89d730831dc7d8c03f6e8f777d52d7e94a016c24daa0a513b7fdb8f13ed4cb94

220 Risk Score

Malware Insights

MITRE ATT&CK

T1204.002 Malicious File Execution: Malicious File T1566.001 Phishing: Spearphishing Attachment T1059.001 Command and Scripting Interpreter: PowerShell

The RTF file contains multiple critical heuristic firings indicating the exploitation of CVE-2017-11882 through an embedded OLE object. The presence of OLE object data and excessive hex data further suggests a hidden payload. The exploitation of Equation Editor is a known method for delivering malicious payloads, likely involving the download and execution of a second-stage artifact.

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.
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.
\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 ~1711KB 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_off00001a92.bin` `59ca6a37719084372c96b86d6d5322f5f91b000b308e8563030259af6c35e678`	rtf-objdata-decoded	RTF \objdata at offset 0x1A92	855836 bytes

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