PDF malware analysis — malicious · 1c859df0d8fa3537

MALICIOUS

PDF

879.7 KB First seen: 2019-04-18

MD5: 40107737005ef38a295018d49b284ca6 SHA-1: 96042f35793987b2a45b6bd2f1c9d1cb9851dba9 SHA-256: 1c859df0d8fa353774e096c197f57c4d66e5256425fa47f50f561a197ce681b6

136 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1059.001 PowerShell T1204.002 Malicious File

The PDF contains embedded JavaScript and an embedded file named 'ukbros001.doc', indicating a likely attempt to deliver a malicious document. The presence of JavaScript actions and embedded files, combined with the ASCIIHexDecode filter, suggests the PDF is designed to exploit a vulnerability and download a secondary payload. The embedded file 'ukbros001.doc' is a primary indicator of the delivered content.

Machine Learning

Nyx PDF Classifier malicious score 0.9999

Heuristics 6

JavaScript action low 2 related findings PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
exportDataObject + nLaunch — embedded-file launch-on-open dropper critical PDF_JS_EXPORT_LAUNCH_DROPPER

PDF JavaScript calls exportDataObject() with nLaunch set, which extracts the document's embedded file and launches it in its default application. This is a launch-on-open dropper: the embedded file is the payload. No benign workflow auto-launches an extracted PDF attachment.
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.
ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX

Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ukbros001.doc`	pdf-embedded-file	PDF EmbeddedFile object 8 at offset 0x38D	299640 bytes
SHA-256: `9b6c516247d99c425f524db25c30491555c36e97e4c3ea3150b11bfc04cfe085`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 22 long base64-like blob(s).
`javascript_obj0009_000.js`	pdf-javascript-stream	PDF /JS object 9 at offset 0xDBD47	62 bytes
SHA-256: `2678576dce9f6de7365365f14636077d9634fba67625c6c6e2eedf7754aa1046`
Preview script First 1,000 lines of the extracted script this.exportDataObject({ cName: "ukbros001.doc", nLaunch: 2 });
`javascript_obj0009_001.js`	pdf-javascript-stream	PDF /JS object 9 at offset 0xDBD47	60 bytes
SHA-256: `88486ab03595b4f28cf88bd93d7422620f386d0bd48c815ccdfd0994d1e3cf3a`
Preview script First 1,000 lines of the extracted script this.exportDataObject({ cName: "ukbros001.doc", nLaunch: 2 }
`combined_document_js_000.js`	deobfuscated-js	combined document JavaScript streams at offset 0xDBD47	123 bytes
SHA-256: `8df1165a5f70cc81c1a5e80a0d8e9e10844a441470676c25789869163bc06ae5`
Preview script First 1,000 lines of the extracted script this.exportDataObject({ cName: "ukbros001.doc", nLaunch: 2 }); this.exportDataObject({ cName: "ukbros001.doc", nLaunch: 2 }

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