Malicious PDF — malware analysis report

Static analysis result for SHA-256 31718bdda9a7fa99…

MALICIOUS

PDF

39.9 KB Created: 2012-12-17 16:05:19 Authoring application: ameuqjcms (via shtqdthq) First seen: 2026-05-09
MD5: e930fa9ba0eec526af7e9720c1156658 SHA-1: d5ef3df8aa5d46dcb937a5d5c152f44c115544d3 SHA-256: 31718bdda9a7fa99323c9a704eaa3ae5980f4fe7dc1eed75eb50f0cd15a4a358
72 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The ML classifier strongly indicates maliciousness in this PDF document. The presence of an embedded file and XFA form further support this assessment. While no specific script was extracted, the combination of heuristics and the ML score suggests the document is designed to exploit a vulnerability and deliver a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9619

Heuristics 6

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ns.adobe.com/xdp/ In PDF document text
    • http://www.xfa.org/schema/xci/1.0/In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.2/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text
    • http://ns.adobe.com/xfdf/In PDF document text
    • http://www.xfa.org/schema/xfa-form/2.8/In PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0016.bin pdf-embedded-file PDF EmbeddedFile object 16 at offset 0x17E9 7076 bytes
SHA-256: a3e490b4dcf23cb3d6b7149b0221fd2e3882b332f9f1601f9ead01d00c872680
Detection
ClamAV: No threats found
Obfuscation or payload: likely
99 of 198 identifiers look randomly generated (e.g. 'DqmhhrsG0BKIAgEAx') — consistent with name-mangling obfuscation.

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