PDF malware analysis — malicious · 172223e366c7c0b1

MALICIOUS

PDF

4.1 KB

MD5: 138e2043b6628c9e138cba46ea63157d SHA-1: 569719bcb219c268dde14368303dfde4cb52e989 SHA-256: 172223e366c7c0b1d754d37c728baaf0bc73b224a8d9fda1045076fd40cfdcb4

258 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF file contains embedded JavaScript that utilizes a custom Base64 decoder and eval() to execute an exploit targeting Adobe Reader (CVE-2008-2992). The script further decodes and executes additional layers, ultimately downloading a second-stage payload from the URL http://93.174.93.11/~cpanlsin/test/x/probing/load.php. The ML classifier strongly indicates maliciousness.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 9

util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992

PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (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://93.174.93.11/~cpanlsin/test/x/probing/load.php

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0013_001.js` `ce3509f9008299699824bedcce2cab0181378c05f1e2d38cbce2b3d7c974fb1c`	pdf-javascript-stream	PDF /JS object 13 at offset 0x368	6461 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` `02239fbe27ff279b876a2804f453db3c6329bed0f2438f9b5bfa15262e2a9ea3`	deobfuscated-js	PDF AcroForm base64 (decompressed) at offset 0x99D	3691 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` `947c40bfaaf4610de2020d10d8614322117560e484d358466b3d06f62615fc35`	deobfuscated-js	custom Base64 decoded JavaScript layer 2 (PDF /JS object 13) at offset 0x95E	2067 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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