RTF malware analysis — malicious · 0548fa47729e5c9b

MALICIOUS

RTF

1.28 MB First seen: 2019-04-18

MD5: 438e9fceeedda7d42c5ddd2c2812e428 SHA-1: d82837b5f57414141052d5b9360a8a317666593d SHA-256: 0548fa47729e5c9b3e6c5a97c345e8f944c1335dc9af363f9f5ea46f8d35dfd3

242 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious activity, including the exploitation of CVE-2017-8570 via composite moniker and embedded OLE objects. The heuristic firings strongly suggest that the file is designed to drop and execute a script, likely a second-stage payload, as indicated by the presence of shellcode API strings in an extracted artifact. The embedded OLE object data, particularly objdata_01_off0000021e.bin, is a primary suspect for containing the malicious script.

Heuristics 8

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.
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~1165KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 7 \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.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.

URL http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 7

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000025.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x25	229 bytes
SHA-256: `bdf6de0a64b3411ca5229f989a8704bb9f2ac8eac0d3b0c83ab62136585dd012`
`objdata_01_off0000021e.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x21E	582883 bytes
SHA-256: `685f9ce722b3e70ff0321c4ddbb963df77e3dd9fe4532ee8da0e87f2996f9e63`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: heap spray 0x04, SC_STR_LOADLIBRARY, SC_STR_CREATEPROCESS Static shellcode analysis recovered API/import strings: LoadLibraryA, VirtualAlloc, kernel32.dll, KERNEL32.DLL, CreateProcessA, CreateThread
`objdata_02_off0013524b.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x13524B	1123 bytes
SHA-256: `263c6a332f8bed14e4d9417cab11f921ef8d301d5b5d655b5a43179ea58c7434`
`objdata_03_off00135b4a.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x135B4A	31700 bytes
SHA-256: `d4a1288d7e1e89b8424faf9a360d1200ca1fa2aa5a80b059536b6305279af68e`
`objdata_04_off0014532a.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x14532A	404 bytes
SHA-256: `392cac683130eb6402c5b549f0e7d1653f531eebb9a09e8b26c73d30cf6c8b98`
`objdata_05_off0014568e.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x14568E	937 bytes
SHA-256: `e21955e19ee5e9c33caa29d20574aba20d6cc02b855734ac20377ad351eddf3c`
`objdata_06_off00145e5e.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x145E5E	2633 bytes
SHA-256: `ce081fd28fe7177ff803b92dfff0940839fdacbc316318ce15cbf8889540f4f0`

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