PDF malware analysis — malicious · 658dd4f877db8746

MALICIOUS

PDF

5.2 KB Created: 2008-08-06 01:42:27 Authoring application: Scribus 1.3.3.12 (via Scribus PDF Library 1.3.3.12)

MD5: b2090580721e11dd959921f281efca6c SHA-1: 1832fe20e71b93573744469210dc3001c03a6a13 SHA-256: 658dd4f877db87462b2519b9086fde5b348296112bb83ee0e34771be42ec4da1

258 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that utilizes a custom Base64 decoder and exploits CVE-2007-5659 (Collab.collectEmailInfo) to execute arbitrary code. The JavaScript is designed to download a second-stage payload from the URL http://91.203.92.136/spl2/load.php?id=282&spl=4. The ML classifier strongly indicates maliciousness.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 9

Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659

PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (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.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (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://91.203.92.136/spl2/load.php?id=282&spl=4

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0013_001.js` `edce474c613a0966297b855cfe625d670d79b3f6c2ae9b26d61c3098389dede6`	pdf-javascript-stream	PDF /JS object 13 at offset 0x365	6757 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).
`acroform_b64_00.js` `47a2edd4442e11233cd8b1068103f74a85d1b0ad1e48781e503ac1d4e96f0671`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x71D	4390 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`custom_b64_stage_000.js` `b4c58e673d92d240b8fd2989e096713c8daac24b4e2a532be815e051ea43521d`	deobfuscated-js	custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x6DE	2661 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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