Malicious PDF — malware analysis report

Static analysis result for SHA-256 628867a33923dcef…

MALICIOUS

PDF

132.8 KB
MD5: afa0f672b4220ce403aa3c4113a318a9 SHA-1: 934aef2c147f46ae0feadbd33d12133df60df083 SHA-256: 628867a33923dcef26e15f2a6435a0657ff3ce31009f30cbe71707884fdfe38b
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 CVEs to execute code. This JavaScript is designed to download a second-stage payload from the provided URLs. The ML classifier and heuristic firings strongly indicate malicious intent, specifically related to exploiting PDF vulnerabilities for code execution and payload delivery.

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://10.brayx.in/x/l.php?s=printf_all2&
    • http://10.brayx.in/x/l.php?s=email_all2&
    • http://10.brayx.in/x/l.php?s=gicon_all2&

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
ba23a937c9afbc71309195634c383a313891933cf9af556a490b87b4739d055b
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
897e37e3c6edf25ebda1585dc96c691334715b0a3dcbb6c04392921fa1f9a972
pdf-javascript-stream PDF /JS object 8 at offset 0x209 135433 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 long base64-like blob(s).
legacy_pdfkit_stage_000.js
ab0aa489198a6cdea9d0799bd1310d92657b12998e8e06c07d3969e433085947
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0xA4A 14781 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s).