PDF malware analysis — malicious · cb027792e62d56e8

MALICIOUS

PDF

135.1 KB Authoring application: PyPDF2

MD5: e4cb78059eaf85179bc4c53d682f42de SHA-1: 82544a62c98819c3b5caf327a9e529e903b0e921 SHA-256: cb027792e62d56e85e59444ac71e685a8c56bf7b4a4f406930a9d699bd090ff9

254 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.002 Malicious File

This PDF file contains embedded JavaScript that is designed to exploit a vulnerability. The script utilizes WScript.CreateObject("WScript.Shell") to create a shell object and attempts to download and execute a second-stage payload. The high confidence in the PDF_JS_WSCRIPT_DOWNLOADER heuristic and the ML classifier output support this assessment. The script's obfuscation and use of WScript indicate a downloader functionality.

Machine Learning

Nyx PDF Classifier malicious score 0.9854

Heuristics 8

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
Embedded script payload in PDF stream high PDF_EMBEDDED_SCRIPT_PAYLOAD

PDF stream bytes contain script execution markers such as ActiveXObject/CreateObject, WScript.Shell, PowerShell, or shell-exec primitives. This is stronger than ordinary PDF JavaScript because it indicates a staged external script payload hidden in stream bytes.
PDF JavaScript WScript downloader high PDF_JS_WSCRIPT_DOWNLOADER

Decoded PDF JavaScript reconstructs a Windows Script Host COM downloader using WScript.CreateObject plus XMLHTTP/ADODB.Stream style download, write, and run behavior. This is commodity payload delivery rather than a specific PDF parser CVE trigger.
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.
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.
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.
AcroForm button with action trigger low PDF_ACROFORM_BUTTON

PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `c9ff428ac43fc09534b3c589cecf8d8f19e9d28a7dbe794b1a400cefcdd4fd49`	pdf-javascript-stream	PDF /JS object 5 at offset 0x2EB	74530 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 4 long hex-escaped blob(s).
`javascript_obj0005_001.js` `bf6a1df41c5d9488f6a3557f8af976870f13ccdeb8aca38afa1c5af0e76ff221`	pdf-javascript-stream	PDF /JS object 5 at offset 0x2EB	112 bytes
`embedded_pdf_script_00000345.bin` `b3f7434058401049e14459ee22d5ff27cdbc7e3346077c76a7e803b14c606572`	pdf-embedded-script	PDF decompressed stream script payload at offset 0x345	138292 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).

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