PDF malware analysis — malicious · b5fa2c8a8e320a1e

MALICIOUS

PDF

15.9 KB

MD5: a46f464d4fb3e6c807cda1820975cdbd SHA-1: b5011fddc5ddc471df96296e8bd023836a539a1e SHA-256: b5fa2c8a8e320a1e196e2e9c0f7a059e49fe2b004d70dcd30dda1069b8fa10d1

96 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, identified as a multi-stage dropper. This script is designed to download and execute a second-stage payload, as indicated by the heuristic 'PDF_JS_OBFUSCATED_DROPPER'. The presence of multiple deobfuscated JavaScript files further supports this finding. The exact nature of the second-stage payload is not detailed in the provided evidence, but the overall mechanism points to a malicious downloader.

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` `4333cfd35d4ddaadd3d452836bd71be2d1d242ace7de70b497e3fd693702cd71`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1B2F	12607 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` `dd75a140617567502a7c1c029704fff3d2b6e9f15d51962692fb43d8f6db8746`	deobfuscated-js	PDF JavaScript deobfuscation pass	61588 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

Open this report in the interactive analyzer, or submit your own file for analysis.