PDF malware analysis — malicious · ab8c5001313824e4

MALICIOUS

PDF

17.0 KB

MD5: f33c114e6ccd4e07f5821f607b804476 SHA-1: dd66931d3a95d737fd1b743f8299eb0b8116d9d5 SHA-256: ab8c5001313824e467344592c70a1982ffb6d5b150c0f29fef7de739e00526ea

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains heavily obfuscated JavaScript, flagged as a multi-stage 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 deobfuscated JavaScript files further supports this analysis. The exact nature of the second-stage payload could not be determined due to the obfuscation, but the overall intent is clearly malicious.

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` `8c65bfb370d7bf87a49e768ed4d0b37b1abeed6b76c218597f0d1aa4b71efd8a`	pdf-javascript-stream	PDF /JS object 5 at offset 0x148	720 bytes
`legacy_pdfkit_stage_000.js` `2a0f1dd8b8ef50c29b408fd27d0c0c884d953bf04d465814684a47d521d67bb1`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1D11	13608 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` `17aba993b9907efe7520977446b593efe06eec4a82ed419f7ae9eac2ec14e373`	deobfuscated-js	PDF JavaScript deobfuscation pass	64493 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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