Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8998d3a1575623f…

MALICIOUS

PDF

65.2 KB
MD5: 2719b6eba12162e8f5f69d858db76dfe SHA-1: c51976ac6a489c764faeb1398b5af589a025cd81 SHA-256: a8998d3a1575623f701a9982d84d853967b1f3855b779ca4cc447ebadd3f06d5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The PDF file contains embedded JavaScript and XFA form elements, which are often used to deliver malicious payloads. Heuristics indicate the presence of JavaScript actions and embedded script payloads. The ML classifier strongly suggests maliciousness. The embedded script, 'embedded_pdf_script_00001fab.bin', is the primary indicator of malicious activity, likely responsible for downloading and executing a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9370

Heuristics 8

  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution
  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
  • 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. (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • 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://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/1.0/
    • http://www.xfa.org/schema/xci/2.8/
    • http://www.xfa.org/schema/xfa-template/2.5/
    • http://www.xfa.org/schema/xfa-template/2.4/
    • http://www.xfa.org/schema/xfa-locale-set/2.7/
    • http://www.xfa.org/schema/xfa-locale-set/2.6/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xfa/promoted-desc/
    • http://www.xfa.org/schema/xfa-form/2.8/
    • http://www.xfa.org/schema/xfa-data/1.0/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off0000034b.js
f574e4d51594d1a8fd22e125b109b827c437aa898edc78babb62dbb93f8744f8		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x34B 1532 bytes
stream_003_off00000536.js
4a1aca004cf20431c9a66dce85404a6411a54d881a6c257882260ffc972a13eb		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x536 870 bytes
embedded_pdf_script_00001fab.bin
30ce21ea1cda0f890aea6e1fb62ad6d22bac2cec62281e587a1efa00b1a2f553		 pdf-embedded-script PDF raw stream script payload at offset 0x1FAB 18125 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
objstm_0039_00.bin
b5ca42bcbfb65caec0b000957c6ba1becb31aae391b45a4887901396e1ca9495		 pdf-objstm-decoded PDF /ObjStm 39 0 obj (inflated) 1395 bytes
font_00_cff_off00000f20.bin
3c3b0837d4cd89f8e38a421a3682b1b05be54c1f94f589e57f50a253a86e7c22		 pdf-font-stream PDF embedded font (cff) at offset 0xF20 1289 bytes
font_01_sfnt_off00007600.bin
3a47365ba29be93b97be381e34ec3c7ef0a10e0f82cdb3dadd6fb11f2800fdb3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7600 36717 bytes

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