RTF / .DOC malware analysis — malicious · 81934595c067d976

MALICIOUS

RTF / .DOC

1.97 MB First seen: 2023-03-01

MD5: 02bfe7a5459d08796f832a7002f6894a SHA-1: f833ae7681b6e11a96ff9874abbf78aa331e2da8 SHA-256: 81934595c067d976cfd890e63f6a3849ae2942fa293fce7604157aefcab3cc59

242 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution when the OLE object is activated, leading to the delivery of a secondary payload. The high entropy and size of the decoded object suggest it contains a packed or encrypted executable.

Heuristics 7

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.
Decoded Equation Editor payload + PE critical RTF_EQUATION_EDITOR

RTF decodes to an Equation Editor ProgID adjacent to OLE activation and the same decoded object stream contains embedded PE bytes. This matches the Equation Editor exploit surface used by CVE-2017-11882 / CVE-2018-0802 documents, while requiring payload evidence to avoid flagging benign Equation references.
\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 ~2069KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 1 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object
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_off00000072.bin` `f6a3121b5f83a4b389e75f522f87708f499d4bdc6e60ebf334b7fd76dc7878c1`	rtf-objdata-decoded	RTF \objdata at offset 0x72	1034787 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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