PDF malware analysis — malicious · 139b95e083d09ea9

MALICIOUS

PDF

13.0 KB

MD5: b98844051c491bf169f0dbefdcae510b SHA-1: acb1bab71fcb086cd00ceaaff8ba3c8a948ef81d SHA-256: 139b95e083d09ea91c928259b3aa9124147a46e9ee460366587a62e41645b6f5

276 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains obfuscated JavaScript that exploits CVE-2007-5659 (Collab.collectEmailInfo) to execute arbitrary code. The deobfuscated script indicates it is designed to download and execute a second-stage payload, likely from a remote source. The ML classifier and ClamAV heuristics strongly indicate malicious intent.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 8

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: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION

ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
Binary-XOR JavaScript stager high PDF_BINARY_XOR_JS_STAGER

PDF JavaScript stores viewer-version payload branches as long binary digit strings, XORs each bit pair, converts 8-bit chunks with String.fromCharCode, and evals the recovered exploit stage.
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.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0049_000.js` `a5a7c3081046e2537cab8fefc095de47f8f6c06bce277d1b27e28b7670984cdc`	pdf-javascript-stream	PDF /JS object 49 at offset 0xA	77116 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
`binary_xor_stage_000.js` `16c05682a41ee00231b49b0cdcf9b74b36c09e49dcd8049eab28f2ef78598e84`	deobfuscated-js	binary-XOR decoded JavaScript at offset 0x3F8	1282 bytes

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