RTF / .DOC malware analysis — malicious · 4a67cc05b5f45a77

MALICIOUS

RTF / .DOC

241.5 KB First seen: 2021-09-25

MD5: 09c275af1fe403ef1955cf691179cb33 SHA-1: 49b1427effc50d6949c45e22fecbbfba4b2380c5 SHA-256: 4a67cc05b5f45a774fafb1da0a0e8ac0f3839a0b520c0b2346bbeeace304aa77

340 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The RTF document contains multiple embedded OLE objects, with one specifically configured for automatic updates (".objupdate"). This indicates an attempt to automatically execute embedded content upon opening, bypassing user interaction for macro enablement. The presence of OLE object data and automatic linking suggests a downloader or dropper functionality, aiming to execute a secondary payload.

Heuristics 9

Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570

RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
CVE-2017-0199 / CVE-2017-8759 (OLE2Link auto-activated remote loader) critical CVE related RTF_OLE2LINK_REMOTE_MONIKER_LOADER

RTF embeds an OLE2Link object that is force-activated with \objupdate (no user interaction on open) and fetches a remote second stage — through an INCLUDETEXT/INCLUDEPICTURE field or the OLE object's own moniker. This is the OLE2Link auto-update attack path shared by CVE-2017-0199 (server returns an HTA/scriptlet) and CVE-2017-8759 (server returns a SOAP WSDL the .NET parser compiles). Office processes the fetched response through the same code path; the specific CVE depends on the now-unreachable server content type.
Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED

RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
Automatically linked OLE object high RTF_OBJAUTLINK

RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
\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
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000969.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x969	26658 bytes
SHA-256: `d9573754b0ca2659cf9ad71daf42c80cf14356068a31cc738f963ed3a6746b12`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): WScript.Shell"")")
`objdata_01_off0000e2a2.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xE2A2	2632 bytes
SHA-256: `9d9bc825f2fa5e0ed8db7dce6823e199ad9c775873472d42887214589f205470`
`objdata_02_off0000f845.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xF845	12297 bytes
SHA-256: `44deae4627fee3c44f54d5bd10477ec2e17f4c08135f08e2417832e36d10d037`

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