RTF malware analysis — malicious · 3876672f635e0e98

MALICIOUS

RTF

177.7 KB First seen: 2020-09-07

MD5: b99633b4350c3aa515fe23981bc1d906 SHA-1: 2ccbdea83594d08f3e03585925c5393c62529e0a SHA-256: 3876672f635e0e9854a9cd990389b11934612d1e1b6efc4948bfcda1b8759290

200 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains OLE object data and specifically triggers heuristics related to CVE-2017-11882, indicating exploitation of the Equation Editor vulnerability. This vulnerability is commonly used to execute arbitrary code, likely to download and run a secondary payload. The extracted artifact 'objdata_00_off00001087.bin' is a shellcode candidate, further supporting this attack vector.

Heuristics 5

Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
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.
\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 1 \objdata section(s) — embedded OLE objects
Suspicious extracted artifact medium 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_off00001087.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x1087	32651 bytes
SHA-256: `af9e0f3ecfd0ef9071e88310e736ac8a57e5e058a86cd7422dd76c2c44e2ea4c`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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