Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ccb69da26914f69…

MALICIOUS

PDF

8.0 KB
MD5: cef2090aebcb503be43d8eeeb4cd3279 SHA-1: 2d46092650a77c30503c63a2594ffbc05a9e7589 SHA-256: 4ccb69da26914f695fdbc1fc9dab20f9639b65a890c5a96397dfc61b0202e7cf
256 Risk Score

Malware Insights

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

The PDF file contains heavily obfuscated JavaScript, indicated by multiple heuristic firings including 'PDF_JS_OBFUSCATED_DROPPER' and 'PDF_UNESCAPE'. The critical 'CVE_2007_5659' firing points to the exploitation of a known PDF vulnerability. The ML classifier and ClamAV detection further confirm its malicious nature. The primary attack vector appears to be the execution of embedded JavaScript, which is designed to download and execute further stages, as suggested by the 'obfuscated multi-stage PDF JavaScript dropper' heuristic.

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)
  • ClamAV: Pdf.Exploit.Agent-36086 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36086
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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, incremental_eval_build, 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.
  • 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_obj0006_000.js
f9b4659beaf681d266cfb5046d495e7b144d406eff72e71ecd4d1451ae25ca11
pdf-javascript-stream PDF /JS object 6 at offset 0x143 481 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
2fc6f10afed87536e30f44a31e1f18764a95a181592887ff611050dcd8c4fc6b
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1A7D 1895 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
4b6c31898116dc1002ea68accd18d6f87cd21fa3a1ac69c716b551292a5af9de
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x329 4972 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
3d896e07b73738d297dfad7ecc2128c3a5e1252e69ad0d249cad55b4224bc5d8
deobfuscated-js PDF JavaScript deobfuscation pass 22428 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).