RTF malware analysis — malicious · ab7c1967bf1fefdf

MALICIOUS

RTF

674.3 KB First seen: 2023-03-30

MD5: 8b41762ba6f5e51ec3960b2b5a87ef2c SHA-1: 3f4925d4dae214db46aa61cf868a32cf88f64e10 SHA-256: ab7c1967bf1fefdffde93626b78eb30994655ab02f59e0adb0935e3e599a953f

200 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains multiple OLE objects, specifically triggering the CVE-2017-11882 vulnerability related to Equation Editor. This exploit is designed to embed and activate malicious code, likely leading to the execution of a second-stage payload. The presence of `Equation.3` as a class name strongly indicates this exploit vector.

Heuristics 6

Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED

RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger 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 3 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object
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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off0000001a.bin` `60da3f7da021ba751ae20789def7d8151d2d44468ea9aaec99b70852ef6b5159`	rtf-objdata-decoded	RTF \objdata at offset 0x1A	343458 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s).
`objdata_01_off000a7b8d.bin` `6ef048de06e9c2e6b420e78a489e52123766b08549a074a5f95b98ffe8558f38`	rtf-objdata-decoded	RTF \objdata at offset 0xA7B8D	1709 bytes
`objdata_02_off000a7b9d.bin` `8935eb605040753f89379b3f05c2cdaefba833ec64299ed9c258020f4c1217b0`	rtf-objdata-decoded	RTF \objdata at offset 0xA7B9D	36 bytes

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