Malicious PDF — malware analysis report

Static analysis result for SHA-256 16e908aa18ed3786…

MALICIOUS

PDF

44.7 KB
MD5: 51c25149babfa55dba834a49c0a406d5 SHA-1: 1c439bad70f56c2fad2da524ba9914f21d8d1d51 SHA-256: 16e908aa18ed37867fc4b4b1e0acb2a4a81d8ff08d0077a923a251f71f8a0e84
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 script is designed to download and execute a second-stage payload from the URL http://femmre.in/nte/kuz.html/yH72a5a478V0100f080006R72ad9774102T3e1fd5e1201l0409327. This is further supported by ClamAV detection of Js.Exploit.Shellcode-18.

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://femmre.in/nte/kuz.html/yH72a5a478V0100f080006R72ad9774102T3e1fd5e1201l0409327
    • 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
7d89f31503ccc0de9b36cd2413c7ad6050bb972a236b719cb9a7b22d6da72891		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3700 bytes
javascript_obj0012_001.js
6e58f430d83cc26365f659f0f6f0a2bf105e12afe4206d7e88afa40915d44a79		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4586 bytes
generic_stage_recovery_000.js
c62343d25f3df4c69cad46dd239bf2d144b45f6781f38000f7a2f86860ce5a3e		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3650 bytes
generic_stage_recovery_001.js
4b8c52ef9c5ab047974db25b8609c0071b381ce535c80bc2082d7e8a896e2703		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4536 bytes
generic_stage_recovery_002.js
c4c54b9f59624dcc486701ab16c1940c097ab08fcb5154fb62bdf94838663a66		 deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0xA0BA 8187 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: unlikely
generic_stage_recovery_003.js
9162d6a93f3f453dcfb8d8cc00c666b86073f7fcb42494e5e2c73e37c42adff5		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45750 bytes
generic_stage_recovery_004.js
a28be296de6ae3c8967a3e832c158846c1ddb10861fcc330b4919ccc1cac08e5		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45798 bytes
generic_stage_recovery_005.js
b709ef9f80ed451c9244a0cdca47c781ef831cbc375884a2204ad5c1f57c2a66		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 45748 bytes
font_00_sfnt_off0000033c.bin
683fcffe9abaad29001e134bdd9ad7d1628d5cbbf628c451b6c621f202a7dae4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x33C 65932 bytes

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