PDF malware analysis — malicious · 07bdb65d7ddee258

MALICIOUS

PDF

2.3 KB

MD5: 747ebcfcaa2e855bf97753a83432b2d9 SHA-1: 39cad87001cccc8873b087c15d8b66af8d1a1759 SHA-256: 07bdb65d7ddee258beea216ba56142fc939ca7d5225bcf297f97d65dab533f0f

358 Risk Score

Malware Insights

MITRE ATT&CK

T1059.007 JavaScript T1203 Exploitation for Client Execution T1071.001 Web Protocols

The PDF file contains obfuscated JavaScript that utilizes eval() and unescape() functions, indicative of exploit code. The script leverages the CVE-2007-5659 vulnerability (Collab.collectEmailInfo) to execute arbitrary code. The deobfuscated JavaScript contains a URL, http://sirokko.in/byban/l.php?i=4, which is likely used to download a second-stage payload.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 11

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.
ClamAV: Pdf.Exploit.Agent-36082 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-36082
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://sirokko.in/byban/l.php?i=4

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 0x84A	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` `552f4ca5f9bb778625b706b3b8521d29ca7a8577096ce304511d38e3f7b52698`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x189	2634 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).

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