PDF malware analysis — malicious · 9f3c1681b8281f3f

MALICIOUS

PDF

16.1 KB

MD5: e6318a8fe3fb1b7135b274a213b22479 SHA-1: 64f3666ee7cdd733d7ac3f732bbf06f90777bae6 SHA-256: 9f3c1681b8281f3f47ca33cc76abba47cd87ba371f239bd0b966788a5762ee53

98 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. Analysis indicates it's designed to download and execute a second-stage payload. The presence of multiple JavaScript streams and the ML classifier's high score support this assessment. The specific URLs or final payloads were not directly extractable from the provided evidence.

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` `73a163f029daba6c0de6a1cc77feb1f8cec8bace2f6eff96e9b7879752edd891`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1B94	12914 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` `856e022949999b46c428c97e31cf5a21fa0cc58923c2445f0965d4f6eaffa408`	deobfuscated-js	PDF JavaScript deobfuscation pass	62755 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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