RTF / .DOC malware analysis — malicious · b12b3b6f87f35d7b

MALICIOUS

RTF / .DOC

432.7 KB

MD5: 8476c8f3efac1a6006ada1f0e18524b7 SHA-1: f28ba53905e5d3324da5926924b6049d9183d301 SHA-256: b12b3b6f87f35d7b2cdb52ec2558f2087155bc5f580b6a9083b05a73263a901f

182 Risk Score

Malware Insights

MITRE ATT&CK

T1204.002 Malicious File T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data, specifically related to the Equation Editor, which is a known vector for exploiting CVE-2017-11882. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_RELATED` heuristics strongly indicates this vulnerability is being leveraged. The `RTF_OBJUPDATE` heuristic suggests that the OLE object is automatically activated upon opening the document. The high entropy of the carved artifact `objdata_00_off00001058.bin` further suggests it contains executable content, likely the second-stage payload. The attack pattern is consistent with a malicious document designed to exploit this vulnerability for initial access.

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.
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.
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_off00001058.bin` `ed3b30b8851c2bb9cdb8c207eba50add3089b803a068c46119c3953b66079cbd`	rtf-objdata-decoded	RTF \objdata at offset 0x1058	219297 bytes
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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