Malicious PDF — malware analysis report

Static analysis result for SHA-256 9a2d8d2a3b125d34…

MALICIOUS

PDF

12.1 KB
MD5: 9b959431f7b3674f58fc55b70f5b9acf SHA-1: fa5f599ec59cde68cfed6cb115f64133bd4964f7 SHA-256: 9a2d8d2a3b125d34f770d3ad13e16c806863bbf49d318b1669101dbdc4201b34
186 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, specifically leveraging the CVE-2007-5659 vulnerability through the `collab.collectEmailInfo` function. This JavaScript is heavily obfuscated and appears to be a stager, indicated by the heuristic `PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER` and the presence of multiple deobfuscated JavaScript files. The primary function of this script is to download and execute a second-stage payload, as suggested by the analysis of the deobfuscated scripts.

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
3efdd2b72a8442c261aa981b6ad3648044aeb32e7ac1ec10a2bdee1c712bfc4a
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5160 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
5c3b8cfaf84e1ea64eb913f79d0e48a4ab99e50c41cb3d92803694601d93efd5
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D6 12313 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
e9204449b5b7bde0670e5c3cfd06dc6c447328445cb17ac61ac400957e1c0c44
deobfuscated-js PDF JavaScript deobfuscation pass 73361 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).