Malicious RTF — malware analysis report

Static analysis result for SHA-256 c57ede8e57655821…

MALICIOUS

RTF

548.0 KB First seen: 2019-09-30
MD5: 9c7d5ca8cea7ade37fd5372025c76a6e SHA-1: 6ecee5a346b6271e1fe0d7b34204f38ba7716aea SHA-256: c57ede8e5765582143bc0652de30cc157b1e25b1384ae42b8e04efbee07fdeb8
340 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains OLE object data and triggers the CVE-2017-8570 vulnerability, which is known to drop SCT scripts. ClamAV identifies the file as Win.Malware.Nemesis-7647563-0, indicating it's a known malware variant. The exploitation likely leads to the execution of a malicious script, which in turn downloads and executes a further stage payload.

Heuristics 7

  • 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.
  • ClamAV: Win.Trojan.Myxah-7541011-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Myxah-7541011-0
  • \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.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 255044 bytes
SHA-256: 200fd1bf37ae4e6c073c6323e5b1acb6803bac8aefa6745114897fbb78f68fe1
Detection
ClamAV: Win.Trojan.Myxah-7541011-0
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off0008642a.bin rtf-objdata-decoded RTF \objdata at offset 0x8642A 1056 bytes
SHA-256: 38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642
objdata_02_off00086ca6.bin rtf-objdata-decoded RTF \objdata at offset 0x86CA6 429 bytes
SHA-256: c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703
objdata_03_off0008703c.bin rtf-objdata-decoded RTF \objdata at offset 0x8703C 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_off00087b48.bin rtf-objdata-decoded RTF \objdata at offset 0x87B48 2633 bytes
SHA-256: 1f8de175e345e5b9624b8bb5f76e9d4c1d78de3a7bbc2750e8ea7def36f04cfb