Malicious PDF — malware analysis report

Static analysis result for SHA-256 4904c5c6831d9ab6…

MALICIOUS

PDF

9.9 KB Created: 2008-04-28 12:17:40 +03:00
MD5: c6a9276eaa931a2e1b2be09b4bc74ecd SHA-1: cae7182edecc6cdb2f5d1d91bff4701353eff1c3 SHA-256: 4904c5c6831d9ab6e1082392697f34a00c1a0abe6abbe97ea3de87689e9b0956
168 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link

This PDF file contains embedded JavaScript that utilizes the `eval()` function and `String.fromCharCode()`, indicating obfuscation. A critical heuristic identified the CVE-2007-5659 vulnerability, specifically targeting `Collab.collectEmailInfo`. The embedded JavaScript is likely designed to exploit this vulnerability to download and execute a second-stage payload. The ML classifier strongly supports the malicious nature of this PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 10

  • Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659
    PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser exited 1. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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.
  • ClamAV scan did not complete on extracted artifact info CLAMAV_SCAN_INCOMPLETE
    ClamAV did not complete on 2 carved artifact(s); EXTRACTED_FILE_CLAMAV may be missing for this run. The result is not cached so a later submission will retry the scan.
  • 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.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0016_000.js
df66221cdaa59f6f8c05690aa0c217925e487b5f1f6199982cfc5b24d8074985		 pdf-javascript-stream PDF /JS object 16 at offset 0x8DB 6892 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_000.js
69a4f16877f0d008b6439307214b8e18d73bd7fc365149505e1c32916160235b		 deobfuscated-js CRC32 callee-key hex decoded JavaScript at offset 0x8DB 2530 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).

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