PDF malware analysis — malicious · 865c51380a739e2d

MALICIOUS

PDF

14.2 KB

MD5: ddea16f095ca60414ee715aa20c95fe5 SHA-1: 3e81503e7dee0a5475609379ee3daab298e2bcf2 SHA-256: 865c51380a739e2dfd43ae8d2be76ec40ec4f0909d09d689fbf2a9d4833f0406

168 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript T1204.002 Malicious JavaScript

The PDF file contains XFA (XML Forms Architecture) which is known to be a vector for exploits. Heuristics indicate the presence of XFA heap spray exploit code and embedded JavaScript. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript, identified as stream_000_off00000043.js, is likely responsible for the malicious payload execution, although its specific actions are not detailed in the provided evidence.

Machine Learning

Nyx PDF Classifier malicious score 0.9995

Heuristics 6

XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT

PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
XFA JavaScript heap-spray exploit code critical PDF_XFA_HEAP_SPRAY

PDF contains XFA script content with heap-spray or shellcode-like JavaScript markers such as large encoded word sequences, util.pack, large arrays, or spray variable names. This is a weaponised Adobe Reader exploit pattern, not a normal interactive form.
Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD

PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
XFA form low PDF_XFA

PDF uses XML Forms Architecture — can contain script logic
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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`stream_000_off00000043.js` `e742d2e9d2d1957f20206fa53d4ac72095a99cbe9845b6e1b34e424fc9213cfd`	decompressed-pdf-stream	PDF FlateDecoded stream at offset 0x43	4194304 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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