Malicious PDF — malware analysis report

Static analysis result for SHA-256 7c2cb405516400f0…

MALICIOUS

PDF

44.7 KB
MD5: fa6bf16717f83ace8b95714765fb8973 SHA-1: 6fbdc3d2c14601c45990248659814038481b42f9 SHA-256: 7c2cb405516400f01a52be12cc80043c52eda2c0468c4561a51c3df85aac1fcc
336 Risk Score

Malware Insights

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

This PDF file exploits CVE-2010-2883, a known Adobe Reader vulnerability, to execute embedded JavaScript. The JavaScript is designed to download and execute a second-stage payload from the URL http://jeurep.in/nte/kuz.exe/yH89230fa8V0100f080006R7bfbc7af103Tc59911b8201l0409327, as indicated by the 'PDF_JS_SHELLCODE_DOWNLOAD_URL' heuristic and ClamAV detection '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://jeurep.in/nte/kuz.exe/yH89230fa8V0100f080006R7bfbc7af103Tc59911b8201l0409327
    • 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
f92b97738a2a596174ba9634269787cb228f215c00179058f69a241be007950c		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3700 bytes
javascript_obj0012_001.js
8949a0e693d19f611321a1c166d55715615bd450287c3808869f07c6d7d1add9		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4586 bytes
generic_stage_recovery_000.js
0b44b7ec6710c87e0cac103a27de6864e3102b08b9ffaf473351c0064dd41a31		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3650 bytes
generic_stage_recovery_001.js
b38571dc371c0e64288705620397211629f3a1b16cbcd557d050530137abb843		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4536 bytes
generic_stage_recovery_002.js
ed08c904ed69196b3e10ed8d82bc15db986032fac39eb99087dbfb5566b4a3bf		 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
3118b47605fbfafd0e958a01b4822d93ba73c5d2610b34f69e8f28abc5834824		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45750 bytes
generic_stage_recovery_004.js
b7a665b3b5593e412d9213bf995e702e5b5245537988798ecf767f7b658f9c0a		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45798 bytes
generic_stage_recovery_005.js
227e60eb8dfccd3a3cdfed8caac03642afdefd53d4965c6e127ee4c79b6c962f		 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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