RTF malware analysis — malicious · 9ce7d688e178ad8c

MALICIOUS

RTF

25.6 KB First seen: 2022-11-29

MD5: eb8f3a597db40cb66cfd9797c79bf9af SHA-1: 6d3a152e59998e3c28cf5f2ad6f9b08929bae60d SHA-256: 9ce7d688e178ad8c103f7f85d4c025bc5fd299ae49125ab42df82b6ca3f5fc1a

220 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.005 PowerShell T1204.002 Malicious File

The sample is an RTF document containing an embedded OLE object that exploits CVE-2017-11882 via the Equation Editor. The heuristic firings strongly indicate this vulnerability is being leveraged to achieve code execution. The document body contains a lure instructing the user to enable editing, a common tactic for macro-based or exploit-laden documents. The primary goal is likely to download and execute a second-stage payload.

Heuristics 6

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.
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.
OLE object data medium RTF_OBJDATA

RTF contains 1 \objdata section(s) — embedded OLE objects
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_off00004f7e.bin` `b4514657b0ae478fd4ea60291b7d19bf19d9396a04d1510585f1fec458e4e49f`	rtf-objdata-decoded	RTF \objdata at offset 0x4F7E	1674 bytes

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