RTF malware analysis — malicious · d66defc2ce75a9b7

MALICIOUS

RTF

5.27 MB First seen: 2023-03-14

MD5: cfcce3ae10933515374bf5b2675b11b1 SHA-1: 2a7df8f6a4e73cc8c81d501d22a631dc4544c6dc SHA-256: d66defc2ce75a9b799e1c79fc8f66309709ce83833f15981ad089c809c792b64

220 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF file contains an OLE object with decoded Equation Editor payload, strongly indicating exploitation of CVE-2017-11882. The presence of excessive hex data within the OLE object suggests it is used to hide a secondary executable payload. No scripts were extracted, and the document body contained only numerical data, providing no further context on the lure.

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.
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 ~5522KB 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000093.bin` `3ef0d1f95554ecb3be82b071a82fa0112666afaec9cca37d71423a7f5091cae6`	rtf-objdata-decoded	RTF \objdata at offset 0x93	2761399 bytes

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