MALICIOUS
258
Risk Score
Malware Insights
MITRE ATT&CK
T1059.007 JavaScript
T1203 Exploitation for Client Execution
The PDF file contains obfuscated JavaScript that leverages the CVE-2007-5659 vulnerability (Collab.collectEmailInfo) to execute arbitrary code. This script decodes and evaluates further layers of JavaScript, ultimately downloading a 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
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Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659PDF 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)
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PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTERPDF 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.
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eval() call high PDF_EVALeval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
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PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URLDecoded 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).
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JavaScript action low PDF_JAVASCRIPTPDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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Embedded JS stream low PDF_JSPDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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String.fromCharCode low PDF_FROMCHARCODEString.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)
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Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGEOne 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.
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Embedded URL info EMBEDDED_URLOne 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.js21bc038a0f4c38bc88c822c13e3a1ada956dd802dcefabf5dbd35058066870ab |
pdf-javascript-stream | PDF /JS object 13 at offset 0x364 | 6844 bytes |
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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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acroform_b64_00.jsbdf086ddd37145cad89f1e539d9b66cd857a9d04b8c186c50e6fe96224b0374a |
deobfuscated-js | PDF AcroForm base64 (decompressed) at offset 0x71B | 4458 bytes |
|
Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s).
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custom_b64_stage_000.js3dde3b9b2485279fd03bc297d02bd8e5e84379ae48eff51357e96680fc6b8c6c |
deobfuscated-js | custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x6DC | 2610 bytes |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 3 eval/decoder/string-building token(s).
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