PDF malware analysis — malicious · 681843faf6d372fe

MALICIOUS

PDF

43.9 KB

MD5: be3141bfbe92c260c36df23cc48d3a39 SHA-1: e4b7483333efee52ec5b166d719e9711b3419ba8 SHA-256: 681843faf6d372fe0bb0627b2c76bc24de7aef2866fcfb6a8360f2b4d3990897

356 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains multiple critical heuristics indicating exploitation of Adobe Reader vulnerabilities, specifically CVE-2009-3459 and CVE-2009-3953 related to U3D content. Embedded JavaScript is obfuscated and acts as a dropper, attempting to download and execute a second-stage payload. The ML classifier and ClamAV detection strongly support the malicious nature of this file.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 10

Adobe Reader U3D auto-activated 3D annotation — CVE-2009-3459 critical CVE likely CVE_2009_3459_U3D_AUTOACTIVATE

PDF contains a /Subtype /3D annotation that is configured to auto-activate on page view (/3DA <</A /PV /AIS /I>>) alongside a /U3D stream and JavaScript. This is the document shape used by CVE-2009-3459 (Adobe Reader U3D CLODProgressiveMeshDeclaration heap overflow, APSB09-15): the U3D parser runs without any user interaction once the page is rendered, while the accompanying JavaScript prepares a heap-spray to land controlled memory inside the corrupted allocation.
Adobe Reader U3D CLODProgressiveMeshDeclaration exploit critical CVE likely CVE_2009_3953

PDF combines malformed U3D 3D content with JavaScript/action activation. CVE-2009-3953 is an Adobe Reader/Acrobat U3D CLODProgressiveMeshDeclaration array-boundary vulnerability triggered by malformed U3D data in a PDF.
U3D/3D content in PDF — Adobe Reader 3D parser CVE-family indicator high CVE related PDF_U3D_CVE_RELATED

PDF contains U3D (Universal 3D) or 3D annotation content — CVE-2011-2462 and CVE-2009-3953 are critical vulnerabilities in Adobe Reader's U3D processing that allow arbitrary code execution. U3D content in PDFs is extremely rare in normal documents.
ClamAV: Pdf.Dropper.Agent-7268651-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7268651-0
Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY

Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER

PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
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.
syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN

PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed 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 6

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `a2765ef4bc176af71164210608f93ccd0cfd1d5803648c48f5d630ef03f5faa9`	pdf-javascript-stream	PDF /JS object 5 at offset 0x14F	749 bytes
`generic_stage_recovery_000.js` `2cddb2bc6087d7e401900b317c670724f2f13cb3e511de2bcf362f30cd1285e7`	deobfuscated-js	generic stage recovery split-literal-normalize from JavaScript object 5 at offset 0x14F	737 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s).
`legacy_pdfkit_stage_000.js` `5fc3654cf02be474df3dd7a2d35aff2588984dfe295e2cb335db70bd2dd1a0e1`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1CB8	13493 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
`legacy_pdfkit_stage_001.js` `b5785e24e163f2203d1fc365c7e491ba6443f26c3efa337e69ad54b44fe74ea1`	deobfuscated-js	nested inline base-23 callee-key decoded JavaScript at offset 0x1CB8	5339 bytes
`deobfuscated.js` `ac24614809613617268cd8ebc79790fb587519fa8a4aa6dd97a3566cca03689a`	deobfuscated-js	PDF JavaScript deobfuscation pass	214039 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).
`u3d_00_off00004329.bin` `fb27c6f6ffe2b08a88f79f344ef3cb4f85460ac81a062194b6fd84ab6e48b628`	pdf-3d-stream	PDF U3D 3D stream at offset 0x4329	28021 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.79, consistent with packed or encrypted content.

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