Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a7b10afa5c6296f…

MALICIOUS

PDF

7.9 KB
MD5: 9b3f1bef77487256775b869e4aa77d09 SHA-1: f5c31c1b009397d899b4eafc069f436c0280172a SHA-256: 7a7b10afa5c6296f3e658ce2eb386c8d4e4e05a14bb89fdee723a5e5c7c0905e
224 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1071.001 Web Protocols T1204.002 Malicious File

The PDF file contains obfuscated JavaScript, identified by heuristics such as 'PDF_JAVASCRIPT', 'PDF_JS_OBFUSCATED_DROPPER', and 'CVE_2007_5659'. This JavaScript is designed to act as a dropper, likely downloading and executing a second-stage payload. The presence of 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' further confirms its malicious nature. The attack pattern involves exploiting PDF vulnerabilities to achieve code execution.

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-35901 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 5 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, hex_dashed_payload, 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.
  • 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
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 5 at offset 0x148 469 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
abc4f6c0c2aeedbbbcd2c08d28363021a2a8a297891fe2011f5a201c7fe87007
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x1AE2 1636 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
0ec16dab676873837a324a4a5161eabe56a06cba04117ec43990a6b01b94bcba
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x34B 4941 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
9c5f845d1e3c51a15d153d5692d0f4afc37b5a2ebf85c49d82cb7f08d3d84f8e
deobfuscated-js PDF JavaScript deobfuscation pass 47247 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).