RTF / .DOC malware analysis — malicious · b9ef91015d894ef7

MALICIOUS

RTF / .DOC

29.0 KB First seen: 2023-01-24

MD5: b46e00e44324f90a797dae714a4cc7d4 SHA-1: 358154f88d48d0b09a1a0b2dd1b01c1d24c61642 SHA-256: b9ef91015d894ef785bbba54bd741d73866c7b5a4583ec87c470d748399f9ffd

200 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model

The sample is an RTF document that contains an embedded OLE object specifically targeting the Equation Editor vulnerability (CVE-2017-11882). The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates an attempt to exploit this flaw. The `SE_ENABLE_LURE` heuristic suggests the document prompts the user to enable content, a common social engineering tactic for macro-based or exploit-laden documents. The exploit likely facilitates the execution of a secondary payload.

Heuristics 6

Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR

RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
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.
\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
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00005a09.bin` `e6a27f208754cb45e0b8b2d610be78f841666945866bbc3cbbb61f989192e8a1`	rtf-objdata-decoded	RTF \objdata at offset 0x5A09	1877 bytes

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