Malicious PDF — malware analysis report

Static analysis result for SHA-256 0af2497e17b5c1b8…

MALICIOUS

PDF

44.7 KB
MD5: 9b8935191a166c1451bc74054dbe6875 SHA-1: 8a5bb37a624b3a3ef265ad04893378ad8d25a2f2 SHA-256: 0af2497e17b5c1b8cb5e15896be5edd67f78d09bee5f63addd234f5013222eef
336 Risk Score

Malware Insights

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

This PDF document exploits CVE-2010-2883, a known vulnerability in Adobe Reader, to execute embedded JavaScript. The JavaScript code contains a shellcode download URL, indicating it attempts to download and execute a second-stage payload from http://fasted.in/nte/KOHA.py/yH0448cb68V0100f080006R86b10be4102T48f24bc1201l0409327. The presence of XFA forms and JavaScript exploit indicators further supports this attack pattern.

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.py/yH0448cb68V0100f080006R86b10be4102T48f24bc1201l0409327
    • 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
ff2d978b1651976049da4efef37b22019e43acb4e621a7221d8a0a52fabde7a2		 pdf-javascript-stream PDF /JS object 12 at offset 0xA0BA 3688 bytes
javascript_obj0012_001.js
d9a24b612545cea68c0de56e12eebdefb21984422276d15fdb7f6fc155420238		 pdf-javascript-stream PDF /JS object 12 at offset 0xA100 4574 bytes
generic_stage_recovery_000.js
2c6e861960d3bc5bc6a47e143a81662b6431aff05a9ac0e58f8dfa8e5741f971		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA0BA 3638 bytes
generic_stage_recovery_001.js
132e5c67834642ec14611bec43dc740a288255847f13a710d69aaf6e50bc41cb		 deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 12 at offset 0xA100 4524 bytes
generic_stage_recovery_002.js
a491347fac633fcd0c200ea841d4b917230c7c45d60e7ec6d0850012e489c704		 deobfuscated-js generic stage recovery split-literal-normalize from combined JavaScript objects at offset 0xA0BA 8163 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: unlikely
generic_stage_recovery_003.js
cd910ce9242fcf6f4bedfeee137591ac5cf939c1e3ee27da5f11939768a6e94d		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 45738 bytes
generic_stage_recovery_004.js
c968dbca46418b1a66e40e4c17057bff9a1d6b3dcb53618ddc85ea7c6643c0a9		 deobfuscated-js generic stage recovery percent-decode from decompressed stream at 0x0 at offset 0x0 45786 bytes
generic_stage_recovery_005.js
b1507357389fcd964d8de7c7c2ca63567c538a03ae6e4339564d35581bae8614		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 45736 bytes
font_00_sfnt_off0000033c.bin
683fcffe9abaad29001e134bdd9ad7d1628d5cbbf628c451b6c621f202a7dae4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x33C 65932 bytes

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