Malicious PDF — malware analysis report

Static analysis result for SHA-256 37b1cef11f95c8d7…

MALICIOUS

PDF

26.2 KB
MD5: f0b71d0a1a75a92a1bc6be271e4c8ba8 SHA-1: 8fd17a0d073f6b729193375d9c88affb39d99d33 SHA-256: 37b1cef11f95c8d76c7781fed3d3cb57b917beb6c976ade45b2a31bcc19dab54
156 Risk Score

Malware Insights

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

This PDF file exhibits multiple high-severity heuristic firings related to embedded scripts and XFA forms, strongly indicating malicious intent. The ML classifier also flagged it with very high confidence. The presence of `unescape()` and `String.fromCharCode()` calls suggests obfuscated JavaScript is being used to execute a payload. An embedded file was also detected, likely containing the secondary stage of the attack. The exact nature of the payload is unclear due to obfuscation, but the overall pattern points to a malicious PDF dropper.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • XFA form contains risky executable script high CVE related PDF_XFA_SCRIPT
    PDF embeds an XFA form whose script block contains exploit, submission/launch, or shell-execution primitives. Ordinary LiveCycle print/update scripts are left as generic XFA/JS signals unless stronger behavior is present.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits
  • 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
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
  • 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/
    • http://www.xfa.org/schema/xfa-template/2.5/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin
98577c23e3b037bc1f66e16bf62e28f4464a777595a03f4b0f73079571ed4e7d		 pdf-embedded-file PDF EmbeddedFile object 8 at offset 0xC6 26083 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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