RTF / .DOC malware analysis — malicious · 4d190fffe482e994

MALICIOUS

RTF / .DOC

1.40 MB First seen: 2023-09-15

MD5: 1d615678fe4e768a0b8ff9f15d4a2884 SHA-1: cf5c72330c3f6448e6db9323f459ec516803a6bb SHA-256: 4d190fffe482e99437ee796ee1b2e66938dfd77100ede00584733ec5442f6716

242 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document containing an embedded OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code when the OLE object is activated. The presence of a PE file within the decoded object data strongly suggests that the document is designed to download and execute a secondary payload.

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 ~1463KB 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_off0000008b.bin` `be4bdc70c3e70c555f32de32d45eea3a5d7ebb8c4c89fa2623993964d1fdea18`	rtf-objdata-decoded	RTF \objdata at offset 0x8B	731919 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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