Malicious PDF — malware analysis report

Static analysis result for SHA-256 6fcc1bcb82c29e8a…

MALICIOUS

PDF

359.8 KB
MD5: ab7574b0044fc4b1b0e65b07b7181727 SHA-1: 0d59386185f546adfc0fd1e44c641c9f0a801bc6 SHA-256: 6fcc1bcb82c29e8a72d09dec7b07bab44f97b54d6f3093fb7676b97504baf0d6
186 Risk Score

Malware Insights

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

This PDF document is heavily obfuscated and utilizes JavaScript within an XFA form, a common technique for hiding malicious content. The embedded JavaScript, specifically the 'javascript_obj0027_000.js' file, is designed to execute arbitrary code. The presence of 'PDF_ENCRYPTED_WITH_JS' and 'PDF_JS_EXPLOIT_CLUSTER' heuristics strongly indicates that the script's primary purpose is to download and execute a secondary payload, making it a likely initial vector for a broader attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 9

  • 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.
  • Encrypted PDF carries /JavaScript — payload hidden from static analysis high PDF_ENCRYPTED_WITH_JS
    PDF declares /Encrypt and also references an executable trigger (/JavaScript). Document encryption hides the JavaScript body and stream contents from static scanners — combined with auto-execution indicators this is a known evasion pattern used to deliver weaponised JavaScript that the analyst cannot inspect without the decryption key.
  • ASCIIHexDecode filter (with exploit indicators) medium PDF_FILTER_HEX
    Hex-encoding filter present alongside exploit delivery indicators — often used to hide payload or shellcode bytes
  • JavaScript action low 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.
  • 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://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/
    • http://www.xfa.org/schema/xfa-locale-set/2.7/
    • http://www.xfa.org/schema/xfa-locale-set/2.6/
    • http://www.xfa.org/schema/xfa-form/2.8/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0027_000.js
80d7888ecf9ad9e4d03cd8cc6959f589c8f8783f37d48bb4d7dae53f6684c595		 pdf-javascript-stream PDF /JS object 27 at offset 0x1C0B 8603 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
stream_001_off00000b76.js
672d461752be4a970c8e9721164ce074d252b55d09d46cc09259d2ce4fc09f7f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xB76 1546 bytes
stream_002_off00000e2f.bin
29cf1edfedd4f27f3c450646c5dc2510e6bf9e63eee1cd436ac517a465a2e1bf		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xE2F 1650 bytes
stream_003_off0000119b.bin
0f910ffeec733940f6ba1ae41dc6770eab5d615c05bccc95197878b62c8dc45f		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x119B 2928 bytes
stream_005_off00001728.bin
4a60a9864cdf7382475d51051a03fdc43b32c31eb508893ccfccece34957f9f1		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1728 56 bytes
stream_006_off000017ac.bin
fe122a09d8a0444608fdc5a6f4981a2dbd469f5bbfacb4bdd327c28ccc343e13		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x17AC 149 bytes
font_00_cff_off000051e4.bin
ea8f409c7366ed46eeb553aa7b404f04641f482ba88463fbe253da60be5787e5		 pdf-font-stream PDF embedded font (cff) at offset 0x51E4 1138 bytes
font_01_sfnt_off000058c3.bin
e31f8c8507e52f29008d946a00becde9f839e34cb108985ce66167bf881adafa		 pdf-font-stream PDF embedded font (sfnt) at offset 0x58C3 8084 bytes
javascript_obj0029_000.js
626e60fde0ef0d52da53659f2c66a4d3e018147163685aded57c07ae5a963b1e		 pdf-javascript-stream PDF /JS object 29 at offset 0x1E2A 8603 bytes

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