Malicious PDF — malware analysis report

Static analysis result for SHA-256 0453a57780b76a3e…

MALICIOUS

PDF

92.8 KB
MD5: 8ba170c065827f4d6e7c427570fdd77f SHA-1: 47d26446800b03c7137af630c383b523f390009d SHA-256: 0453a57780b76a3e8e2d2d482a0b567f29095bfb76c8d5bdb3f931c35184953e
150 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that exploits CVE-2009-4324 via the media.newPlayer API. This script is designed to download a second-stage payload from the URL http://bestsunstar.com/sss/p.php?e=8&&. The ML classifier strongly indicates maliciousness, and the presence of shellcode download URL confirms the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • 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)
  • 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).
  • 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.
  • 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://bestsunstar.com/sss/p.php?e=8&&

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
ca1eff55f5956c66e9ecf1fc2930f944b63b8411b7f1bccacfc9b7f39e85a087		 pdf-javascript-stream PDF /JS object 8 at offset 0x1E7 2578 bytes
javascript_obj0008_001.js
20d91632d2113cb0153bd77e0f60471af9528ceea5ecb0438f2db46ea40ec05c		 pdf-javascript-stream PDF /JS object 8 at offset 0x209 94542 bytes
legacy_pdfkit_stage_000.js
ada8be7fcbbba2749cefe5122fc7e86dce72eb1b6eeddf6c5a324ca92ef02182		 deobfuscated-js repeated-marker hex decoded JavaScript at offset 0xC2D 2546 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
42025b552c7960b53abcd8cd732b01c8d109eccfdfefc352b9826c4d5807d414		 deobfuscated-js cross-stage annotation API aliases at offset 0x1E7 81 bytes

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