PDF malware analysis — malicious · a80f0a1446c3ef4a

MALICIOUS

PDF

16.3 KB

MD5: d1000d61209834c82d2ef5412d41465d SHA-1: 3622db4f5d12bb266008ac5c6c4eb4efb56e58f0 SHA-256: a80f0a1446c3ef4a2b3bdc286342af05b486d052152950927c5c0f0ac55efd71

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. This script is designed to download and execute a second-stage payload, as indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic. The presence of multiple JavaScript streams and the ML classifier's high confidence score further support its malicious nature. The extracted artifacts 'deobfuscated.js' and 'legacy_pdfkit_stage_000.js' are likely components of this dropper mechanism.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 5

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` `c3bcd973d3afe50233b8d7a730d7d6554b1fc938df31aa1ce1b85f6595cb05bc`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BEB	12870 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` `5ce091657911fe65d1d3b2f3857f06dc5ccb4d868a4dc1f22490a370ab290f81`	deobfuscated-js	PDF JavaScript deobfuscation pass	64012 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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