RTF malware analysis — malicious · 704b8d133970e8c5

MALICIOUS

RTF

6.21 MB First seen: 2021-05-29

MD5: 22be0f416d9c8e7e52560ec748cb432e SHA-1: 9224f0d281be23b4bb7bd57b1fcfbba958a13a9a SHA-256: 704b8d133970e8c593eb5fac70d6ff178bbeb5cb9e995df83fe4c9db655c126c

222 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data, specifically related to Microsoft Equation Editor, which is indicative of exploitation for CVE-2017-11882. This vulnerability allows for the execution of arbitrary code, likely to download and run a second-stage payload. The presence of a large, high-entropy OLE object further supports the conclusion that a malicious payload is embedded within the document.

Heuristics 6

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.
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~6515KB of hex-encoded data inside \objdata sections — may hide a payload
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_off000000ac.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xAC	3257735 bytes
SHA-256: `0623069f3718ee10226072495ac99cfeabf21e9293cfbf864fcbdd9efb88de25`
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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