Malicious PDF — malware analysis report

Static analysis result for SHA-256 16e74dcb52890957…

MALICIOUS

PDF

44.7 KB
MD5: d58a49ef91320b2927f4c43ba8fe8e1f SHA-1: 2f603644ad1638efd00f30357ae0ccbb87ac7dca SHA-256: 16e74dcb528909570247d189483eeba67980da76d04c475c371d5428f3ca9b99
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 vulnerability in Adobe Reader. The script is designed to download and execute a second-stage payload from the URL http://fasted.in/nte/KOHA.html/yH3efc4b7fV0100f080006R59e915ca102T7246241a201l0409327. This indicates a typical exploit delivery mechanism for malware.

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://fasted.in/nte/KOHA.html/yH3efc4b7fV0100f080006R59e915ca102T7246241a201l0409327
    • 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
4b5fc6101cac2da9506d440f59116593bbaa7d03f413f158bb5e2ffbb9eb3f02		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3694 bytes
javascript_obj0012_001.js
98ed9e4e87d9b1f3a9f42ee61be77c9d6be104c764ffc9ca12937890cc26f286		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4580 bytes
generic_stage_recovery_000.js
3c0d84d68c63af3cbd958daa06514e4c3e0360841207e9da8f426ff227b16e44		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3644 bytes
generic_stage_recovery_001.js
8032b3a4f3e7db6b80d6bc1522f4c66d66fa86a4dcca9a27215a973d774b85c8		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4530 bytes
generic_stage_recovery_002.js
cb79e9124c2a0eb60bdf2872b5d86f70304337cb10aed7fc27288e4fb8d2eabf		 deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0xA0BA 8175 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: unlikely
generic_stage_recovery_003.js
9dd77015f313217a8088fa694a82c1d93dc462d5fc697d53250e79f2281dacce		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45744 bytes
generic_stage_recovery_004.js
fc80d98ca88865ec180949d84283539495d1e763cbb4ec08619c5176b89e7334		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45792 bytes
generic_stage_recovery_005.js
8f56dabfa7ae5496c28bc2f1f5f89e3346191773f42f836f253f0bd2b4798302		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 45742 bytes
font_00_sfnt_off0000033c.bin
683fcffe9abaad29001e134bdd9ad7d1628d5cbbf628c451b6c621f202a7dae4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x33C 65932 bytes

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