Malicious PDF — malware analysis report

Static analysis result for SHA-256 ff81fcf6f1f59217…

MALICIOUS

PDF

76.5 KB
MD5: 699676aaa44e82f067104c801f11a944 SHA-1: 87386c2d61585840b8fd7effbd8306b9ca4d6057 SHA-256: ff81fcf6f1f59217a47a65b32ea5c06f19d9c0569b7b846d7d1e3b401f1d77f8
226 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1204.002 Malicious File

The PDF file contains obfuscated JavaScript that utilizes a binary-XOR stager to decode and execute a second-stage payload. The critical heuristic 'CVE_2007_5659' specifically identifies the use of 'Collab.collectEmailInfo' to exploit a known vulnerability in Adobe Reader. The recovered JavaScript is XOR-encoded and uses String.fromCharCode, indicating a deliberate attempt to hide malicious code. The primary intent is to leverage this exploit to compromise the user's system.

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)
  • ClamAV: Pdf.Exploit.Agent-13247 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-13247
  • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0004_000.js
f3256ee6a3652b5c5a67c00065babfaa68a816535ce0258c00983f0558d7fd3d
pdf-javascript-stream PDF /JS object 4 at offset 0xC0 78010 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
917ba7577903ac8dae9ca9258383ec500ee979df2b82480b8a9f01796bebe57b
deobfuscated-js binary-XOR decoded JavaScript at offset 0x3D7 1279 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).