PDF malware analysis — malicious · 398d98bb306b13c4

MALICIOUS

PDF

16.3 KB

MD5: 38e53937344438f1e1b3f056f4f89ebf SHA-1: 76127e8c830b6f04a5b9a3227aad3e6bf914baae SHA-256: 398d98bb306b13c42c1150b27912fb1ab68b289b4a3b015be65ae68efc82da5f

156 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell

The PDF contains obfuscated JavaScript, flagged as a high-confidence dropper. The JavaScript is designed to download and execute a second-stage payload, as indicated by the 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' heuristics. The presence of multiple anti-analysis checks within the JavaScript further supports its malicious intent. The specific ClamAV detection name 'Pdf.Dropper.Agent-7250429-0' is included as a primary IOC.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 6

ClamAV: Pdf.Dropper.Agent-7250429-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7250429-0
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` `926d54219d2e18e77281360cfad431c13562ec52eeacb315f3f8bb0b95bf3b4e`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x1BDE	12840 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` `c4d56c978b962304ab8c592610d56cb1139aa226a28343e87f7cc0fd8ba1bfe1`	deobfuscated-js	PDF JavaScript deobfuscation pass	69735 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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