Malicious PDF — malware analysis report

Static analysis result for SHA-256 5e9fe61f1d5b51b9…

MALICIOUS

PDF

12.3 KB
MD5: 7cef130c5c1c244e000885f29739f8bc SHA-1: 1e3c43f4a3e7ac47c40569ec058c035296b0bc9f SHA-256: 5e9fe61f1d5b51b98bea2df1c060e5ec752247238ed82f829ff18deda1de13f8
116 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that is obfuscated using character code manipulation. The script's primary function appears to be downloading and executing a second-stage payload from a remote source, indicated by the use of `app.openDoc` and subsequent JavaScript execution. The ML classifier and exploit cluster heuristics strongly suggest malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
d2233358777d1aaed8efae57eefbdc7f0ddc83b20eb36c734bc8ee388da7c061
pdf-javascript-stream PDF /JS object 5 at offset 0x107 1418 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).