Malware Insights
The PDF file contains embedded JavaScript that exploits multiple known vulnerabilities including CVE-2009-4324, CVE-2009-0927, and CVE-2007-5659. Static analysis detected obfuscated JavaScript streams, and heuristic analysis identified these as malicious, specifically noting the use of String.fromCharCode and the exploitation of PDF vulnerabilities. The extracted JavaScript is likely responsible for downloading and executing a second-stage payload, as indicated by the ClamAV detection of 'Js.Exploit.Shellcode-18'. The specific vulnerabilities targeted suggest an older exploit kit or a custom exploit leveraging these known weaknesses.
Heuristics 8
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media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324PDF 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)
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Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
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Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
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ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAVClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
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JavaScript action low PDF_JAVASCRIPTPDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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Embedded JS stream low PDF_JSPDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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String.fromCharCode low PDF_FROMCHARCODEString.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. (matched inside decoded stream)
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Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGEOne 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.
Extracted artifacts 3
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
javascript_obj0039_000.js01ff97b894ed5eaa73f893f09448057eb97e8a254b7796755073c3ed7ac81378 |
pdf-javascript-stream | PDF /JS object 39 at offset 0x16F | 20606 bytes |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 1 eval/decoder/string-building token(s).
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legacy_pdfkit_stage_000.js120d086d0b76d7e18b4806f4b762b312618aad12b1f2f30254bf572fb1708769 |
deobfuscated-js | numeric array XOR decoded JavaScript at offset 0x16F | 5416 bytes |
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Detection
ClamAV:
Js.Exploit.Shellcode-18
Obfuscation or payload:
likely
Carved artifact contains 9 eval/decoder/string-building token(s).
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legacy_pdfkit_stage_001.js8e76b89962a3ff1175434556061a1f846e3fe1c67c8a2b2bd1d1bb8cf58a4001 |
deobfuscated-js | numPages XOR decoded JavaScript at offset 0x16F | 5416 bytes |
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