PDF malware analysis — malicious · 0313a5b32853bd77

MALICIOUS

PDF

225.3 KB First seen: 2026-05-11

MD5: ad6f1666e4dbcb2ea6f4124d36a29ad5 SHA-1: 2632d242835729d15654b0446019f3d43e9e0904 SHA-256: 0313a5b32853bd77469d49c03c99ef2d79e7c7b561202ac5e3d4f7ec23c0f294

70 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains an embedded file that could not be fully decoded, indicating a potential attempt to hide a malicious payload. The ML classifier strongly flagged this PDF as malicious, and the presence of an undecodable embedded file suggests an exploit or downloader is present. The file's structure and the ML score point towards a malicious document designed to execute further stages.

Machine Learning

Nyx PDF Classifier malicious score 0.9984

Heuristics 5

PDF embedded file could not be fully decoded medium PDF_EMBEDDED_FILE_UNDECODED

A declared PDF /EmbeddedFile stream uses filters that the scanner could not decode. The raw stream was carved for artifact triage because malformed or unsupported attachment filters can hide payload content from normal extraction.
Embedded file low PDF_EMBEDDED

PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
XFA form low PDF_XFA

PDF uses XML Forms Architecture — can contain script logic
PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED

The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PSSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
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 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`embedded_file_obj0001_undecoded.bin`	pdf-embedded-file-undecodable	PDF EmbeddedFile object 1 at offset 0x54; filter decode failed	229795 bytes
SHA-256: `6b71d001a5a50a1e9b8ce57abe39b98894b6eb6e50fcc817e648125bf0a8c33a`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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