Malicious PDF — malware analysis report

Static analysis result for SHA-256 8084af4e49e792d6…

MALICIOUS

PDF

4.8 KB Authoring application: zsrb
MD5: cd1d7c2b10d4fbc6b4eb3aa99b00e26a SHA-1: 4e0890fa329914154b60917c36a607421c2033ed SHA-256: 8084af4e49e792d6fa4fa215a22071a810fdfbb963d32886029ba8226939a1c8
72 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains an embedded JavaScript payload, indicated by the 'PDF_EMBEDDED_SCRIPT_PAYLOAD' heuristic. The ML classifier strongly flags this PDF as malicious. The extracted JavaScript file, 'stream_001_off000002b4.js', is likely responsible for executing the malicious activity, potentially downloading and running a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • 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.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. 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.

FilenameKindSourceSize
stream_001_off000002b4.js
e935fddd84fe11b17bfc1cb4453c4d58478917c397d49cdb243adf0a90048c48
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x2B4 42546 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 long base64-like blob(s).