Malicious PDF — malware analysis report

Static analysis result for SHA-256 0b6e3f024fcdc587…

MALICIOUS

PDF

2.7 KB Created: 2008-08-06 01:42:27 Authoring application: Scribus 1.3.3.12 (via Scribus PDF Library 1.3.3.12)
MD5: 3a735de291dd504963a595a20d895820 SHA-1: df43dfbf0bc64eb95fec185bc9694ed45747d079 SHA-256: 0b6e3f024fcdc5870e8498f79d149ac5d0a2e3dab7db34218973d2d2f05efa93
370 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript that exploits CVE-2007-5659 (Collab.collectEmailInfo) to download a second-stage payload. The deobfuscated JavaScript explicitly contains the URL http://a311.ru/fiesta/load.php?id=87&spl=4, which is highly indicative of a downloader or exploit delivery mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

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. (matched in decompressed stream)
  • 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.
  • ClamAV: Win.Trojan.Agent-34667 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Agent-34667
  • 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.
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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://a311.ru/fiesta/load.php?id=87&spl=4

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0013_001.js
e962b6b5d595d138a4d84827c91edcb7b7add17bfc74f2c814198ca0f581f597		 pdf-javascript-stream PDF /JS object 13 at offset 0x36A 2641 bytes
Detection
ClamAV: Win.Trojan.Agent-34667
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
combined_document_js_000.js
6fe2dfb5b8aca18917c05da073b4307630b5e4b9f80de5acef9f50f0b51ef9b9		 deobfuscated-js combined document JavaScript streams at offset 0xF 2661 bytes
Detection
ClamAV: Win.Trojan.Agent-34667
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).

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