Malicious PDF — malware analysis report

Static analysis result for SHA-256 6e3e5dab9ba9d86a…

MALICIOUS

PDF

44.8 KB
MD5: 967bc2c3d9c01a8bc0a4f919f34e2544 SHA-1: 1e3709e737b8ceeeba074d4ee4f5fc5be2317a3b SHA-256: 6e3e5dab9ba9d86a0cbfb54e1e924605fc426cce6e08919be4cf1c6ca49173ff
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 attempts to download a payload from the URL http://fasted.in/nte/koha.asp/yHf5e0bd9dV03f01036002R544d7e65102Tb95a1aa7Q000002e9901801F0055010aJ15000601l0409327, which is indicative of a downloader or initial access exploit. The presence of XFA forms and JavaScript exploit indicators further supports this conclusion.

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.asp/yHf5e0bd9dV03f01036002R544d7e65102Tb95a1aa7Q000002e9901801F0055010aJ15000601l0409327
    • 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
4396fe3006f9faa8ac6a46eaf1363595765e5625a3b1b7dfcb3e410415a8827a		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3778 bytes
javascript_obj0012_001.js
abeaaec442a7ae728e78f6656fc458cc8cf7395570fc03dac919c2caeac6cc09		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4664 bytes
generic_stage_recovery_000.js
5a6f5496004289b6217fdb90bdf2b4f400bbbff01aec42f03f7ddeb3b772efb9		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3728 bytes
generic_stage_recovery_001.js
5eb81408e743aab35e45481d62ab71658e1e1f7d6ba326b083cc6b5394077ba8		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4614 bytes
generic_stage_recovery_002.js
f070edf05a04b7588c6f0df250d24ec690acbf61632e085004141bef45a1b08b		 deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0xA0BA 8343 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: unlikely
generic_stage_recovery_003.js
95851f65dc645b8365f9947241e8eeb7901ad21e5d5f5654918bea2fbcdb5298		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45828 bytes
generic_stage_recovery_004.js
063302091e69df2d15fa22f9dfb757d05a094df8f8eb98922a67adedf35e9d51		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45876 bytes
generic_stage_recovery_005.js
df9c92a6a6beb13a4ca587ec2149a6b14a994826dcd3ea0d3940cc1d551426c7		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 45826 bytes
font_00_sfnt_off0000033c.bin
683fcffe9abaad29001e134bdd9ad7d1628d5cbbf628c451b6c621f202a7dae4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x33C 65932 bytes

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