Malicious PDF — malware analysis report

Static analysis result for SHA-256 5dee63fd81bad766…

MALICIOUS

PDF

118.6 KB
MD5: 7d7e3b49a96462614fe608f1da499ee6 SHA-1: 82ed31d2bbecc3691cc45c83a906f0f5d0400bad SHA-256: 5dee63fd81bad766703475b22943f5b7411c8b2dd77f49a89db52f78ac14a8fd
256 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode() functions, indicating an attempt to obfuscate malicious code. Heuristics and ClamAV detection confirm this is a known exploit pattern for PDF files. The JavaScript is likely responsible for downloading and executing a secondary payload, as suggested by the 'exploit cluster' and 'stager' heuristics.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER
    PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.
  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • Large comment-padded JavaScript eval stager high PDF_JS_LARGE_COMMENT_PADDED_EVAL
    PDF JavaScript contains a very large stream padded with long random-looking block comments around String.fromCharCode and eval. This is an exploit-kit obfuscation shape used to bury a decoder and recovered stage inside noise, not normal PDF form automation.
  • 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.
  • 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. (matched inside decoded 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0006_000.js
a36fdbde1051463c4fe896317c00820886f0c65cf80d21b0cdbe8d399217cc52
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627282 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 42 long base64-like blob(s).
stream_002_off0001d883.bin
61c4274975f6c31b267961b8ade77c44f821dd0f43bd191be5005534dfec6650
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D883 200 bytes