Malicious PDF — malware analysis report

Static analysis result for SHA-256 4eb2b90f9e108ebb…

MALICIOUS

PDF

45.2 KB
MD5: 546cf2f232ee37ab8f916bcd2b6b6260 SHA-1: 3a5614d3703bbac5cb450cd4e678af5a81c67d0b SHA-256: 4eb2b90f9e108ebb2e6537e9197626d570214544d1007cf0a62ed1116a5cb22c
246 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript T1566.001 Spearphishing Attachment

The PDF sample contains embedded JavaScript that utilizes unescape() and is associated with an exploit cluster targeting XFA forms. Critical heuristics indicate exploitation of CVE-2010-2883, an Adobe Reader CoolType SING font exploit. The JavaScript likely serves as a dropper for a second-stage payload, although the exact download URL is not explicitly reconstructed from the obfuscated shellcode.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • Embedded script payload in PDF stream medium PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • 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
  • AcroForm button with action trigger low PDF_ACROFORM_BUTTON
    PDF contains a /Btn form field together with a SubmitForm/URI/Launch/JS trigger — this is the building block of fake 'Download' or 'Open' button overlays used in PDF phishing lures
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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://www.bitstream.com
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/3.0/
    • http://www.xfa.org/schema/xfa-template/3.0/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0001_000.js
da40eea18ded9b22e10dddda848eeb3679dde669f204ea89ee388b7522fe01b7		 pdf-javascript-stream PDF /JS object 1 at offset 0xA 2362 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
stream_002_off0000ab9d.js
d1dfd457a2fdd3cec4091f689f39b85b35666aa5599ef3a8d5f9a80d1e2ce105		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0xAB9D 1042 bytes
font_00_sfnt_off00000de2.bin
0f5375894219906a60ca16cd887ad8760d32e7e6d1e344ca6490eefcf719cce3		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDE2 65932 bytes
font_01_type1_off0000b03e.bin
c6bf78478c9c4dd5b3b86554d34c78f847f70af4118f9ff083c1fccf0e8e932b		 pdf-font-stream PDF embedded font (type1) at offset 0xB03E 97 bytes
font_02_type1_off0000b2c6.bin
b749644b3e758e7335900ab2e7499eaa64b3a946849f1f8a0948287bdd96763d		 pdf-font-stream PDF embedded font (type1) at offset 0xB2C6 144 bytes

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