Malicious PDF — malware analysis report

Static analysis result for SHA-256 646733ec767a7a2c…

MALICIOUS

PDF

44.8 KB
MD5: 1d49d4ff554c30f1056c2babcae965b3 SHA-1: 01cea4e2bfafbe73c23087d166080d8d6c8482a5 SHA-256: 646733ec767a7a2c12d61b0d18c956fa7ca6cab8bf7bcd7d23aabe16c6355568
336 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that exploits CVE-2010-2883, a known Adobe Reader vulnerability. The JavaScript is designed to download and execute a second-stage payload from the URL http://jeurep.in/nte/KUZ.asp/. This indicates a multi-stage attack aimed at client execution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 10

  • Adobe Reader CoolType SING font exploit — CVE-2010-2883 critical CVE likely CVE_2010_2883
    PDF embeds a TrueType/OpenType font with an actual SING table and pairs it with JavaScript heap-spray shellcode. This matches the public Adobe Reader CoolType SING exploit shape for CVE-2010-2883.
  • 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.
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV 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.
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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).
  • 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
  • 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://jeurep.in/nte/KUZ.asp/yHbe8053c8V03f01036002R32ab879b10aTf23a6aa1Q00000000900801F0035010aJ0e000601l0409327
    • http://www.bitstream.com
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/

Extracted artifacts 9

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0012_000.js
d86443732c202918b6aa4a9ce76e12a734097a057c2a056f7dab4a1fdbe7c093		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3790 bytes
javascript_obj0012_001.js
371adf70998e17ff04504fdfc156208a9bbc1b70ca75ec46c4e5b6269e8a2493		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4676 bytes
generic_stage_recovery_000.js
0ad643b1a91e57483bfe3eb058fdc883572eabcd544f8d3bf0b3a47b772c6b17		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3740 bytes
generic_stage_recovery_001.js
a167dd34df5288ca169854c4741a62463a0377d10f4a5483068691d681c133a9		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4626 bytes
generic_stage_recovery_002.js
297da983618ce9ea08f3112beb4bd68b0b32faad1da063699853ff7525722a56		 deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0xA0BA 8367 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: unlikely
generic_stage_recovery_003.js
bd688c5d19b251e8634c45b38c9a9b5c628fdda5848f66b844555e9a434a468c		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45840 bytes
generic_stage_recovery_004.js
471c11aca9bde04700ab4982476ab5b97ad4423a01bf215e6e4646d037eb78eb		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45888 bytes
generic_stage_recovery_005.js
14efdf2e145a33a339882b8be975ff3f52ebd9cee6703c1d1ac5b38adc54bca7		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 45838 bytes
font_00_sfnt_off0000033c.bin
683fcffe9abaad29001e134bdd9ad7d1628d5cbbf628c451b6c621f202a7dae4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x33C 65932 bytes

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