RTF / .DOC malware analysis — malicious · 95234858228466c0

MALICIOUS

RTF / .DOC

344.7 KB First seen: 2021-10-31

MD5: a4959089026f1960d66b9527d959c05b SHA-1: 731b9d526f7096db390802adb38d80de794bbff0 SHA-256: 95234858228466c0cefc1506334679d07c6a3838ba0646471a5bd37f70c91a32

182 Risk Score

Malware Insights

MITRE ATT&CK

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

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The ".objupdate" directive forces the activation of this OLE object, leading to the execution of the embedded payload. The high entropy of the carved artifact suggests it is likely a packed or encrypted executable.

Heuristics 5

Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED

RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact 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
Suspicious extracted artifact info 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000015df.bin` `2574859ea6102263887e8ba8782e4ceb0651098a535c891dcaf0b2de87ebf77f`	rtf-objdata-decoded	RTF \objdata at offset 0x15DF	173572 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.

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