PDF malware analysis — malicious · 05a4da3f24c1b2ec

MALICIOUS

PDF

9.5 KB

MD5: da4fcea5719c3e0883c872ae286674f1 SHA-1: 5a2845c38fb2ee2c2e0ffb5bf38c662e827ae3eb SHA-256: 05a4da3f24c1b2ec3605c546fdd07141e63bda009fd19a6c4d66226b4e728d4b

146 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file utilizes XFA forms with embedded JavaScript. The JavaScript function 'hx' decodes a hex-encoded string from the 'subject' property and then evaluates it using 'eval()'. This indicates the PDF is designed to download and execute a secondary payload, likely through the evaluated script. The ML classifier strongly suggests malicious intent.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

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.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
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)
Embedded script payload in PDF stream low 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.
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://ns.adobe.com/xdp/
- http://www.xfa.org/schema/xci/1.0/
- http://www.xfa.org/schema/xfa-template/2.4/
- http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`embedded_file_obj0041.bin` `7181ba29a55b43a5156e94b359a7dc87502cf9cef4a981b8837b61174b91371b`	pdf-embedded-file	PDF EmbeddedFile object 41 at offset 0x52	1162 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`deobfuscated.js` `513d7177b6040cc692d690f041720021e018fa9f7df0e9549b9d95908fa26f96`	deobfuscated-js	PDF JavaScript deobfuscation pass	1792 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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