Malicious PDF — malware analysis report

Static analysis result for SHA-256 162b99fa0d82dab2…

MALICIOUS

PDF

83.2 KB Created: 2006-10-03 13:54:05 -05:00 Authoring application: OmniForm Premium (via APJavaScript 2.2.1 Windows SPDF_1112 Oct 3 2005)
MD5: 0894fc9a8e67ffee951af08f3b781810 SHA-1: 6099f54789a5c64c4b736bc3190d8e9e17746d27 SHA-256: 162b99fa0d82dab25c55dffdb8dccb1fbd5b4ff7f9c8ce08e05fb3fd49ce8e68
186 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, identified as a PDF JavaScript exploit cluster and a generic recovered JavaScript exploit stage. This script is designed to download and execute a second-stage payload, indicated by the 'PDF_GENERIC_STAGE_RECOVERY' heuristic. The presence of XFA forms and embedded scripts strongly suggests a malicious intent to exploit vulnerabilities and deliver further malware. The URL http://www.bitstream.com was found within the extracted data, though its reputation is unknown.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 9

  • 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.
  • 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.
  • 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
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/iX/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/pdfx/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/
    • 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 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_007_off000142de.js
d1dfd457a2fdd3cec4091f689f39b85b35666aa5599ef3a8d5f9a80d1e2ce105		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x142DE 1042 bytes
generic_stage_recovery_000.js
ab688be86dd829123447cc5ec3c99e2956d5102604d5281b39c900923f897d96		 deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0x0 at offset 0x0 85124 bytes
generic_stage_recovery_001.js
04b8f95925acc02f1e087dacc8dd276a57dc95e932e1be05c58e81ecf2cfc2be		 deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from decompressed stream at 0x0 at offset 0x0 85122 bytes
font_00_sfnt_off000076d4.bin
2ad26b2ffa64e65438cb92c9a615a29b74fdbaefdead05f27bf68b6653717311		 pdf-font-stream PDF embedded font (sfnt) at offset 0x76D4 65932 bytes
font_01_type1_off0001478c.bin
c6bf78478c9c4dd5b3b86554d34c78f847f70af4118f9ff083c1fccf0e8e932b		 pdf-font-stream PDF embedded font (type1) at offset 0x1478C 97 bytes
font_02_type1_off00014a1b.bin
b749644b3e758e7335900ab2e7499eaa64b3a946849f1f8a0948287bdd96763d		 pdf-font-stream PDF embedded font (type1) at offset 0x14A1B 144 bytes

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