Malicious PDF — malware analysis report

Static analysis result for SHA-256 79577900c2f3b101…

MALICIOUS

PDF

8.1 KB
MD5: b7cd334039ed70783b5fc5217b7ffc78 SHA-1: 14fa99397361398a599d45bbb771ff1e7b01a5a0 SHA-256: 79577900c2f3b101c66b3edd235c6a894c0a6c3c71748e8305e0fc8219179cbc
158 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF sample contains embedded JavaScript that utilizes eval() and String.fromCharCode(), indicating obfuscated code execution. This cluster of heuristics strongly suggests the JavaScript is designed to exploit a vulnerability within the PDF viewer to achieve arbitrary code execution. The primary goal is likely to download and execute a second-stage payload, although the specific URL is not directly extractable from the provided evidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9224

Heuristics 7

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules. (matched inside decoded stream)
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules. (matched inside decoded stream)
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • Suspicious extracted artifact info 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off00000328.bin
143663f67efeddcc3c12961508d245809f72f83a9744b9baac5b3def18d88284		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x328 2997 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
objstm_0024_00.bin
64d31ee0bbda581dee1303a32fe5211744a2088944541e3dfa1af3c9f3aa6d3a		 pdf-objstm-decoded PDF /ObjStm 24 0 obj (inflated) 380 bytes

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