Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f9a400f9034a299…

MALICIOUS

PDF

12.0 KB
MD5: b8fe7cc2e9812601df85efd3940c895e SHA-1: 70b93d32d0512681a7f79216bc7957f34c6557f6 SHA-256: 3f9a400f9034a299d6e114cfe3e2d6373231dd645e29fee0d83d5d25c4c2f7d9
186 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript/JScript T1204.001 Malicious Link/URL T1071.001 Web Protocols

The PDF file contains embedded JavaScript, identified by multiple heuristics including PDF_JAVASCRIPT and PDF_JS. A critical heuristic, CVE_2007_5659, indicates the use of the Collab.collectEmailInfo function to launch a JavaScript stager. This stager is heavily obfuscated but appears to be designed to download and execute a second-stage payload. The ClamAV detection further confirms the malicious nature of the file.

Heuristics 7

  • 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-36063 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36063
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final 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.
  • 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_obj0007_000.js
eb39e2de4dbbc100de6d3e30aa43ff78fa075618862ba1ebba5151ea3a3b848d
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 273 bytes
annotation_subject_callee_hex_stage_000.js
381200d250b6ddc3eb509fb3b162d0ac82ad1f3738997f083dbdf14489ae7de0
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5085 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
8721d626eb35fd300b7caf7cb48a2a68336aff3ecd4214f7cb29e64efd7c5e10
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D6 12243 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
0bae73f3f1222c6922fdf332efb6b9dfa41b4a51171cada01276ec3def747ad7
deobfuscated-js PDF JavaScript deobfuscation pass 73792 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).