Malicious PDF — malware analysis report

Static analysis result for SHA-256 08fd4a1c5fe7c395…

MALICIOUS

PDF

132.6 KB
MD5: 8e4a198675128fb2d14c0e4faaa8ef33 SHA-1: 35c9ea5111b6d578eb99d6166d35cae1cf72c40b SHA-256: 08fd4a1c5fe7c3956128ac9d22e1c87feae1dde094d1a01e5f0a4b4bc7262cb8
330 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that exploits multiple known vulnerabilities (CVE-2009-0927, CVE-2007-5659, CVE-2008-2992) to download a second-stage payload. The JavaScript is obfuscated but appears to construct URLs for downloading the payload. The extracted URLs are suspicious and likely lead to the execution of malicious shellcode, as indicated by ClamAV detection.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 9

  • Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927
    PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
  • 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)
  • 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 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.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • 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://czkey.in/x/l.php?s=printf_all2&
    • http://czkey.in/x/l.php?s=email_all2&
    • http://czkey.in/x/l.php?s=gicon_all2&

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
f58dbc15b26cbd5d0297151eac558bcd09406a0e8cde871864f8d7844bc15774
pdf-javascript-stream PDF /JS object 8 at offset 0x1E7 2095 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
javascript_obj0008_001.js
569ee4eec1c0d89782c88f544e8f65251ae63ae530d97741147d1ffce4e3c53f
pdf-javascript-stream PDF /JS object 8 at offset 0x209 135217 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 long base64-like blob(s).
legacy_pdfkit_stage_000.js
4acdf6e5855e6b5812a39fcb33ec62188d0457c7bbfd7e0fe3c39ba2243e3d60
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0xA4A 14757 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s).