RTF malware analysis — malicious · 1b4bce02f434168e

MALICIOUS

RTF

1.41 MB First seen: 2022-12-18

MD5: c5e2005e8aae239d1693fb572f60104c SHA-1: 3b9737f64df1f828ca05e0e6bd8a518710c49063 SHA-256: 1b4bce02f434168e956cdcd3eb9eebae87d64f6244e73ae5831be2e6e62f913f

180 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1559.001 Component Object Model and Distributed Component Object Model

The RTF document contains multiple indicators of exploitation for CVE-2017-11882, specifically through the Equation Editor object. The presence of \objupdate and RTF_EQUATION_EDITOR heuristics strongly suggests that the embedded OLE object is designed to be activated, leading to arbitrary code execution. No specific malware family could be identified, but the exploit mechanism is clear.

Heuristics 5

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.
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.
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

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000011df.bin` `e72605db70d30a0f28346cbebe0986cabf38534342335588ce4b43c15af93644`	rtf-objdata-decoded	RTF \objdata at offset 0x11DF	44943 bytes
`objdata_01_off0002ffb4.bin` `8c096ec1776129338dcb83ae72e14898dda300a25f8fb33beda989ad784dac72`	rtf-objdata-decoded	RTF \objdata at offset 0x2FFB4	242154 bytes

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