Malicious PDF — malware analysis report

Static analysis result for SHA-256 67fa147113c5bd38…

MALICIOUS

PDF

118.6 KB
MD5: 693ecacd39936af997b6673b7bd904ef SHA-1: bcad921dff650c5c8d59de026aaf252f461e16ed SHA-256: 67fa147113c5bd386954cc3298de89020cbb32a922b756c792c2ee0e4e402210
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains obfuscated JavaScript that utilizes eval() and String.fromCharCode, indicating an attempt to exploit vulnerabilities and download further malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely involving the execution of a second-stage payload. The presence of JavaScript points to T1059.007, and the overall exploit behavior aligns with T1203.

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
7f503e35985ba5cf088b0bca65dbdac8d4dac418ef64c5ac03b429872324bf65
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627042 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_001_off0001d6b6.bin
ea375bb1bfeeb7d31492132adf2e49187f90fa7785de92cfadb0d651ab84c347
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D6B6 300 bytes