RTF malware analysis — malicious · fd0e5f8b5124e9cf

MALICIOUS

RTF

1.05 MB First seen: 2020-07-24

MD5: e505622edd1f7a2993835daf77f87713 SHA-1: 22026e920c7025f4923ceb80cfb457f460989f8c SHA-256: fd0e5f8b5124e9cf2eaa922df223c619c780d16d59f93e07449539c5ba3e8687

220 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of malicious activity, including embedded OLE objects and specific heuristics pointing to the exploitation of CVE-2017-11882 via the Equation Editor. The presence of decoded object data and shellcode command strings further suggests that this exploit is used to deliver a secondary payload. The file's structure and the identified exploit strongly indicate a spearphishing attachment attack vector.

Heuristics 6

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 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.
\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.
Suspicious extracted artifact high 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.
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

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000fd7.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xFD7	13530 bytes
SHA-256: `b0448674f1e09969ea09bbf6b2d4dcf40157f8de7aa2e2c7af11f44df3a733f7`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): WScript.Arguments.Count - 1, WScript.Arguments(I), WScript.CreateObject("WScript.Shell")
`objdata_01_off000085ca.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x85CA	261 bytes
SHA-256: `fcaaaa5fccca401b369d0b1d30e5179b7dfb0673abfe91f5f06443f82ef2d3ec`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): CmD.exe /C cscript %tmp%\Soma.vbs
`objdata_02_off000097c4.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x97C4	274721 bytes
SHA-256: `34a561a942bbd73c497013c93513f2412de940ee87ec121291f50bad9c786e09`

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