Malicious RTF — malware analysis report

Static analysis result for SHA-256 a2c3c1fe3f4dfdfb…

MALICIOUS

RTF

138.3 KB First seen: 2019-10-01
MD5: ec7546579b51335a970f8d59b9889d8f SHA-1: d12776f3c896f61be68a95b796ea8b2f662107a1 SHA-256: a2c3c1fe3f4dfdfbf6cdd4ab1309a36e10dbe9c3d0e6cce98229bfe3ce7b539a
142 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains an embedded OLE object with a suspicious Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The presence of shellcode API strings within the decoded object data further supports this. The file likely serves as a malicious attachment delivered via spearphishing, aiming to execute arbitrary code on the victim's system.

Heuristics 5

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
  • \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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00021e70.bin rtf-objdata-decoded RTF \objdata at offset 0x21E70 1354 bytes
SHA-256: ee61de49c3940a16011baf1ccdb4a47639a64f960ec55631207c7f956c0f48d1
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_STR_LOADLIBRARY, SC_STR_URLDOWNLOAD, SC_PEB_ACCESS Static shellcode analysis recovered API/import strings: LoadLibraryW, GetProcAddress, URLDownloadToFileW, ExitProcess, ShellExecuteW