PDF malware analysis — malicious · 99560be4947a7fdd

MALICIOUS

PDF

16.3 KB

MD5: 9dd7633d5ac31c082a79d9ba82642fbc SHA-1: 1c5833b7da5c6600140419904b5c94fa299b81d6 SHA-256: 99560be4947a7fdd74a386597a35a5a6e7abc63d2d2c4d4b070cb5e22b789539

156 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged by multiple high-confidence heuristics, including 'PDF_JS_OBFUSCATED_DROPPER'. This script is designed to act as a dropper, likely downloading and executing a second-stage payload. The ClamAV detection 'Pdf.Dropper.Agent-7285433-0' further confirms its malicious nature as a dropper.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

ClamAV: Pdf.Dropper.Agent-7285433-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7285433-0
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 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0005_000.js` `a3319192cac6d4dc4eeb6af2d736b0ffec979b23116a003bc7c23382761c32a5`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	733 bytes
`legacy_pdfkit_stage_000.js` `048bd88747cca555a3fd405cf39a9a6fc6bff3c1d873f55b32ae8fab8fb79c9a`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BCB	12841 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).
`deobfuscated.js` `077621957a32982f2e47c5bf3ae292464f8ea9cc03a9c518f626b498c6813f50`	deobfuscated-js	PDF JavaScript deobfuscation pass	61338 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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