RTF malware analysis — malicious · 6abcd1fbef24f2dd

MALICIOUS

RTF

2.42 MB First seen: 2023-05-18

MD5: 1e9451eed3cec1b182217eaa9e162d23 SHA-1: 841d3ad3042f9dd8789651fef23ef8214c25f5df SHA-256: 6abcd1fbef24f2ddb399ce1261b255295a4960285741bff302e21b7b77b6403d

342 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains multiple indicators of malicious activity, including OLE object data and embedded OLE objects. Crucially, it triggers CVE-2017-11882, a known vulnerability in Microsoft Equation Editor, which is used to activate and execute a hidden payload. ClamAV also detected this as Rtf.Dropper.Agent-9965975-1, indicating its dropper functionality.

Heuristics 9

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.
PE header (with DOS stub) in hex data critical RTF_MZ_HEX

Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
\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.
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~1543KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 2 \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 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00080059.bin` `7b0df79d0fe1191799d54cf93fbe0579b4c2a6d7d24334d2ee11f4e4382947cc`	rtf-objdata-decoded	RTF \objdata at offset 0x80059	523280 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.
`objdata_01_off0018a5c4.bin` `778f9f0a70e56737c679ea50d4a9598ed2c7ccbf07af21befc64d3d0c4b2e39f`	rtf-objdata-decoded	RTF \objdata at offset 0x18A5C4	187272 bytes

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