Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b8a10cab8cb376f…

MALICIOUS

PDF

74.7 KB
MD5: 9eebc8ec94f7a43e94865ca3dbc875cb SHA-1: d85c31f382ebd03edaf07e97a65855a30149dff5 SHA-256: 5b8a10cab8cb376fdd88413984269aa5faf4020d0fef3f6f45f79f7e898aa972
256 Risk Score

Malware Insights

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

This PDF file contains obfuscated JavaScript that exploits CVE-2007-5659 (Collab.collectEmailInfo) in Adobe Reader. The JavaScript is further obfuscated using binary-XOR encoding and string concatenation, indicating an attempt to evade detection. The primary goal appears to be the execution of a second-stage payload via the exploit.

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
4e52cc21f0607ea469c6101e4ff1f06ce246632d58c321ab587a5b84e88047d3
pdf-javascript-stream PDF /JS object 4 at offset 0xC0 76181 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
ce06abf8ad35b9cd4b858e8a5d0485fa186842801c76e19529374057c181ee8a
pdf-javascript-stream PDF /JS object 4 at offset 0xE3 76292 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
0d891a651370ca5b4f48a97d6ef2de6e0224aa6b9569968b2141a55f9a0b862c
deobfuscated-js binary-XOR decoded JavaScript at offset 0x65AE 1237 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).