Malicious PDF — malware analysis report

Static analysis result for SHA-256 5bdc35053336fe20…

MALICIOUS

PDF

74.5 KB
MD5: a3832122bdf898fc301d786e612c4ab2 SHA-1: 25bfa6224a64809a98d3e858738345087aae7f68 SHA-256: 5bdc35053336fe204537568e2e4910dfb3093e76d8cc1b593289e45089d9f80c
256 Risk Score

Malware Insights

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

The PDF sample contains obfuscated JavaScript that exploits CVE-2007-5659 via the Collab.collectEmailInfo method. The JavaScript is further obfuscated using binary-XOR encoding and string concatenation, indicating a deliberate attempt to hide its malicious functionality. The primary goal appears to be the execution of a second-stage payload.

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
cc3922a6aa29d94393f71c28a8666b3306c7d85547de69f07b06b8f3284f5971
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
27f0b43bc5a8ad5c14854ac932b64796d66ca1be04b8d952b82bcc7ad3b74690
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).