RTF malware analysis — malicious · f6ed00024799a080

MALICIOUS

RTF

2.98 MB First seen: 2023-09-20

MD5: 790fe61107ab269e5bac5a605f3c4df3 SHA-1: bc624029c96a388e3bc2e1bd4f9cee8ffbb1a3e6 SHA-256: f6ed00024799a0805589a69c72076a74d27a8e00d044802f34d51f4192649a9f

280 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains multiple indicators of exploitation for CVE-2017-11882, including RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics. The presence of large hex-encoded data blocks within OLE objects, specifically containing a PE header, strongly suggests that the document is designed to drop and execute a secondary payload. The RTF_MZ_HEX finding confirms the presence of a Windows executable within the embedded data.

Heuristics 7

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.
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
\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 ~2071KB 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000800a1.bin` `6996de20483f2fa4b61ce731fde1bf40eb3219708a8932dc68dd9b39f62e5a68`	rtf-objdata-decoded	RTF \objdata at offset 0x800A1	788065 bytes
`objdata_01_off0020bdb6.bin` `4a82d047d6ef350abf1adf2f1f3cef562ce575c77ef4edb29c91f5ec96920c07`	rtf-objdata-decoded	RTF \objdata at offset 0x20BDB6	198784 bytes

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