Malicious PDF — malware analysis report

Static analysis result for SHA-256 0df330a029eb73f3…

MALICIOUS

PDF

359.1 KB Created: 2009-08-28 16:04:52 +08:00 Authoring application: Acrobat PDFMaker 8.0 for Word (via Acrobat Distiller 8.0.0 (Windows))
MD5: a0bbff6b298263bc5e8d79d199658254 SHA-1: 2d244bd82a4d3b62d8b001328698c55ef5a08202 SHA-256: 0df330a029eb73f30a0232d6ab541ccd66f600a121b47610e255e3145ce7a895
212 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that utilizes a base64 decoding function and then unescapes the result. This pattern is indicative of a dropper mechanism designed to download and execute a secondary payload. The critical heuristic 'PDF_JS_EXPLOIT_CLUSTER' and ClamAV detection 'Pdf.Dropper.Agent-7228603-0' strongly suggest malicious intent. The exact nature of the second-stage payload could not be determined due to truncation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9946

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.
  • ClamAV: Pdf.Dropper.Agent-7228603-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Dropper.Agent-7228603-0
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (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.
  • 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.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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/pdf/1.3/
    • http://ns.adobe.com/pdfx/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0022_000.js
23196a541ff8f8d8b16a18d75f587d6253535851e0524b193beb8ce9131e3b29		 pdf-javascript-stream PDF /JS object 22 at offset 0x57FDF 10727 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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