Malicious PDF — malware analysis report

Static analysis result for SHA-256 603bdaabdcafbdcf…

MALICIOUS

PDF

74.5 KB
MD5: f1da3b0f6a4d02b3f7f09364e66a2f55 SHA-1: c1ec2d490396a97223b45809c8f4e9572ef88e74 SHA-256: 603bdaabdcafbdcf1ff9be9a55504bd3ccd5c454d472983b618e7d97e8c64a13
256 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript T1190 Exploit Public-Facing Application

The PDF file contains obfuscated JavaScript that leverages the CVE-2007-5659 vulnerability (Collab.collectEmailInfo) to execute arbitrary code. The JavaScript is further obfuscated using binary-XOR encoding and string concatenation, indicating an attempt to evade detection. The primary function of the script is to decode and execute a second-stage payload, likely for further system compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 8

  • 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)
  • 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.
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution
  • Binary-XOR JavaScript stager high PDF_BINARY_XOR_JS_STAGER
    PDF JavaScript stores viewer-version payload branches as long binary digit strings, XORs each bit pair, converts 8-bit chunks with String.fromCharCode, and evals the recovered exploit stage.
  • 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.
  • 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.
  • 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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0004_000.js
37424c41d8037999c0490468f627685e7284cb6bf0254f837fe6a39f68ddc0f8
pdf-javascript-stream PDF /JS object 4 at offset 0xC0 75994 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
javascript_obj0004_001.js
8ecdee2babf94746d660cdf86ec82958f77b6262caf6c927bb2490c7496b007c
pdf-javascript-stream PDF /JS object 4 at offset 0xE3 76105 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s). Carved artifact contains 6 long base64-like blob(s).
binary_xor_stage_000.js
7c838c8c6e50294331de6b4fbbfe3ea7c3c195c087e7dcd8fb9c58179fae563c
deobfuscated-js binary-XOR decoded JavaScript at offset 0x3D7 1237 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).