Malicious PDF — malware analysis report

Static analysis result for SHA-256 a40df4465de2f6c0…

MALICIOUS

PDF

5.3 KB Created: 5318-13-25 49:65:95 -34:09 Authoring application: Acrobat Editor 8.0 (via Adobe Acrobat 8.1.0)
MD5: 5ae98a64db15c18896771189eab9da19 SHA-1: 06d0ac2e6e3f85af839c3f5c2a1743403dff3d73 SHA-256: a40df4465de2f6c0c75ad78ce4622f2f7d0e76d039217d2a80b9626a5bb283b2
278 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that utilizes the `eval()` function and `String.fromCharCode()` to decode and execute a malicious payload. The critical heuristic `CVE_2008_2992` indicates the use of a known Adobe Reader exploit, specifically targeting a vulnerability that allows for arbitrary code execution. This payload is likely designed to download and execute further stages of malware. The ClamAV detection further confirms the malicious nature of the file.

Heuristics 10

  • util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992
    PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
  • ClamAV: Pdf.Exploit.Agent-35551 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35551
  • 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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • String.fromCharCode medium PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically (matched inside decoded stream)
  • Suspicious extracted artifact medium 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.
  • 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.
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PSEOF. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0028_000.js
da28397fbd00ebe1bed1f7772b00ae122f380f4ca22161d5101a23a85b957fe9		 pdf-javascript-stream PDF /JS object 28 at offset 0x4C6 3527 bytes
Detection
ClamAV: Pdf.Exploit.Agent-35551
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
custom_b64_stage_000.js
59acd460c63a6ac0e4e281f2c6f096eb17bf3611e6e56f01dd53c375c174ca95		 deobfuscated-js custom Base64 decoded JavaScript layer 1 (PDF /JS object 28) at offset 0x82C 1986 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).

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