RTF malware analysis — malicious · a861b7b82656e001

MALICIOUS

RTF

65.0 KB First seen: 2019-04-17

MD5: f86d4d0efed59880663de0f887bbe2ab SHA-1: 9bfbf26dbae3edc5cc8a01a81f1b4fb5c714bb73 SHA-256: a861b7b82656e001e64132fac098363cfe1711c25cdf9d2766f53ac22be78e71

220 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple OLE objects and ".objupdate" directives, indicating it is designed to exploit vulnerabilities. Specifically, the "CVE_2017_8570" heuristic firing confirms the use of a Composite Moniker to drop an SCT script, which is a known technique for executing arbitrary code. The embedded OLE object data, particularly at offset 0xB5D2, is the likely source of this exploit.

Heuristics 6

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.
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.
\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 5 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object

Extracted artifacts 5

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000025.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x25	8961 bytes
SHA-256: `b9373c3e15b8cbd0fd298752cf08b329ed74f52cab3b2a04428bc25b1b75e759`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.96, consistent with packed or encrypted content.
`objdata_01_off0000d859.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xD859	1056 bytes
SHA-256: `38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642`
`objdata_02_off0000e0cf.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xE0CF	429 bytes
SHA-256: `c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703`
`objdata_03_off0000e45d.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xE45D	1351 bytes
SHA-256: `fbfe6031f946bf25c25f9783662a0516de4f34007dcfe7ff53f2b540dbc1df3f`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cscript //nologo %vbs%
`objdata_04_off0000ef52.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xEF52	2633 bytes
SHA-256: `1f8de175e345e5b9624b8bb5f76e9d4c1d78de3a7bbc2750e8ea7def36f04cfb`

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