Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf856478f6ffeefb…

MALICIOUS

PDF

8.0 KB
MD5: 76ed4a078cf44a51729dcff0073228f9 SHA-1: b669c1808bf371e6239c1ad17c6e58f6b33090ec SHA-256: bf856478f6ffeefbbf00eb7d962ea73654c8b7c23bd9be81e28f274f1a82b6cb
194 Risk Score

Malware Insights

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

The PDF file contains obfuscated JavaScript that leverages the CVE-2007-5659 vulnerability. The JavaScript is designed as a multi-stage dropper, indicated by the 'PDF_JS_OBFUSCATED_DROPPER' heuristic and the presence of multiple deobfuscated JavaScript files. The primary exploit mechanism identified is related to the 'collab.collectEmailInfo' function within Adobe Reader, which is a known vector for this CVE. The exact payload or final destination is not discernible from the provided static analysis, but the intent is clearly to download and execute further malicious code.

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-15015 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-15015
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 3 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_dashed_payload, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • 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. (matched inside decoded stream)
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0005_000.js
9d5c7e01faed5b04e9ec11f1d98b73f0012c871beaf60e9f9d32ad6df00d46f7
pdf-javascript-stream PDF /JS object 5 at offset 0x148 550 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
ca3793fafc02abefc343b3cf20eb019b68df2a8c511402b2ed24020064ccc0bc
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1ADE 1822 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
0f49fcc1856e8a9f53a09d52fb77bc745f4fa47424234dcc34ffa712ce7d014e
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x359 4976 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
bddbfaa2661855e4b54173911fd1e21d73d0dc419a818e7f906433d83b1c0c87
deobfuscated-js PDF JavaScript deobfuscation pass 22488 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).