Malicious PDF — malware analysis report

Static analysis result for SHA-256 18f7773e28fdc41b…

MALICIOUS

PDF

346.0 KB
MD5: 96921723c630e249d9db9ac8dd144df8 SHA-1: 5ed82cdc062c186048f9cc8b8e38cb83dc9f5c19 SHA-256: 18f7773e28fdc41b07b5122f9906d10d44be8106665896ee85ca23966763a80c
126 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 and triggers heuristics related to PDF JavaScript exploits and XFA forms. The JavaScript code appears to be obfuscated but likely attempts to download and execute a secondary payload from a remote source, indicated by the presence of URLs and the ML classifier's high confidence in maliciousness. The specific URL 'http://www.bitstream.com' is flagged as unknown reputation and is included as a potential indicator of compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 7

  • 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.
  • 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://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xfa/promoted-desc/
    • http://ns.adobe.com/xdp/
    • http://www.xfa.org/schema/xci/2.6/
    • http://www.xfa.org/schema/xfa-template/2.6/
    • http://www.xfa.org/schema/xfa-locale-set/2.7/
    • http://www.xfa.org/schema/xfa-locale-set/2.6/
    • http://www.xfa.org/schema/xfa-form/2.8/
    • http://www.xfa.org/schema/xfa-data/1.0/

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0044_000.js
d04e3450f44051088f29c7aa78421ac3f17c77d1deab536fd91aff2563c9414b
pdf-javascript-stream PDF /JS object 44 at offset 0x33C9 9306 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
font_00_cff_off00006094.bin
ea8f409c7366ed46eeb553aa7b404f04641f482ba88463fbe253da60be5787e5
pdf-font-stream PDF embedded font (cff) at offset 0x6094 1138 bytes
font_01_sfnt_off00006e86.bin
e31f8c8507e52f29008d946a00becde9f839e34cb108985ce66167bf881adafa
pdf-font-stream PDF embedded font (sfnt) at offset 0x6E86 8084 bytes
font_11_sfnt_off0001c43e.bin
422bc5698ba5d9d4818f6a2d8b3abca2f723e713b44a15c390139d2c976a1388
pdf-font-stream PDF embedded font (sfnt) at offset 0x1C43E 65932 bytes
font_12_sfnt_off0002c867.bin
7e24ee16c8b09ee74d61445f29c3c0a95abfdf17fc1008606394f159dbd0c106
pdf-font-stream PDF embedded font (sfnt) at offset 0x2C867 65932 bytes
font_13_sfnt_off0003cc90.bin
57e24925bc6bdb98d38e8b4ba3b87f80f75c5e49ea9a522486790d7dc6848549
pdf-font-stream PDF embedded font (sfnt) at offset 0x3CC90 65932 bytes