RTF malware analysis — malicious · 3ad92d43c4253e63

MALICIOUS

RTF

1.78 MB First seen: 2021-06-30

MD5: 6cc183bd0d50358e8bf68d6811b1bee4 SHA-1: a16c11a57d03684d3c1b73e116285b0d7c55e019 SHA-256: 3ad92d43c4253e6328109ecbc58ac02716b2cdee641dababd44c473d2bf72522

220 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of exploitation, including RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics, pointing to the use of the Equation Editor vulnerability. The presence of OLE objects and the ".objupdate" directive further suggest an attempt to force OLE activation and execute embedded content. The extracted document body contains obfuscated code and references that, combined with the heuristics, indicate a malicious payload execution.

Heuristics 6

Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
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.
Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
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_off000011e1.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x11E1	53952 bytes
SHA-256: `ad1fb5fb70b24f4e53ac2abc60f78c33ed09f74ee0843515b9e8293e9f8133c8`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): Wscript.ScriptFullName
`objdata_01_off0002fdb3.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x2FDB3	454791 bytes
SHA-256: `abd132bf3ab8190dfb030bcb879a36061e9aef78c1060b63bd0588b35c7d316c`

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