PDF malware analysis — malicious · 74b6d60207950429

MALICIOUS

PDF

2.3 KB

MD5: d73481704f64860b7b806d3425a27164 SHA-1: 6b8d67a0b65c709c1514e56efe7224c6f11057bc SHA-256: 74b6d602079504294f39ba703b002ae28e293fb4f9437f7e8b6bff9f65754fdd

418 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF file contains embedded JavaScript that utilizes eval() and unescape() functions, indicative of obfuscated malicious code. This script is designed to exploit CVE-2009-4324, a known vulnerability in PDF readers, to download and execute a second-stage payload from the URL http://193.104.146.51/b/l.php?i=16. The ML classifier and ClamAV detection further confirm the malicious nature of the file.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 12

media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324

PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
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.Exploit.Agent-36082 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36082
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
unescape() call high PDF_UNESCAPE

unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL

Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
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.
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://193.104.146.51/b/l.php?i=16

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj111611_000.js` `772da696bdb365f3f1eb4ea6af881baad391be62f3591b19f2f9827fcc4c9b53`	pdf-javascript-stream	PDF /JS object 111611 at offset 0x820	479 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `f7790d21f222bece810ec3076e2ff47c8aeace26483e0befe674a11caa49fbc4`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x189	2427 bytes
Detection ClamAV: Js.Exploit.Shellcode-18 Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).

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