Malicious PDF — malware analysis report

Static analysis result for SHA-256 86aabd926ab51a5a…

MALICIOUS

PDF

118.6 KB
MD5: 3a9e94bbeca1b100d283b748edb0e4fd SHA-1: 70d0dd42af59137950cc91cb70ef3c5b046997a8 SHA-256: 86aabd926ab51a5ab83879f1885218738c86aee937110a46ff2c618d717239bf
256 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript that utilizes eval() and String.fromCharCode() functions, indicating a high likelihood of malicious code execution. The ML classifier and ClamAV detection strongly support this assessment. The primary function of the JavaScript appears to be downloading and executing a secondary payload, consistent with a common malware delivery technique.

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
a26f2a91735df7db7f53be6ad35e76d36f055f15fe0fad492f6e58cfa19a3138
pdf-javascript-stream PDF /JS object 6 at offset 0x143 627052 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_off0001d8c3.bin
d23a6ae9c7358647c7402ac6d111cd19fc65383777d110aab1f226b5e6a5f38b
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1D8C3 200 bytes