RTF malware analysis — malicious · 4dfe1d5806c98fc9

MALICIOUS

RTF

380.8 KB First seen: 2020-05-25

MD5: 7a5c485d77d01d14f801304337e76ed0 SHA-1: 9db2cd2ed742e7d9077865755e2e49523b0b3010 SHA-256: 4dfe1d5806c98fc9c18debc39dc1c6069c1b55ca2ca30550191b607bb13a9918

262 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains an embedded OLE object that exploits CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This exploit is designed to execute arbitrary code, and the extracted artifact 'objdata_00_off000007b2.bin' is highly suspicious. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_RELATED heuristics confirms the exploitation vector. The file is classified as a dropper, indicating it's likely used to download and execute further malicious content.

Heuristics 7

Decoded Equation Editor payload + PE critical CVE likely 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.
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.
ClamAV: Rtf.Dropper.Agent-7701174-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Dropper.Agent-7701174-0
\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
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_off000007b2.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x7B2	193940 bytes
SHA-256: `db6bd95cf3e70e32d270cb27f3ffbebd87de62d6c866bc476f238da54581a738`
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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