Malicious PDF — malware analysis report

Static analysis result for SHA-256 9dfe1e2b1d7db136…

MALICIOUS

PDF

9.2 KB
MD5: b7526c4458718aadf2f1c73c90825d23 SHA-1: 7fc2682fc4df3b1fe42215a218f07a8ce99bd6a2 SHA-256: 9dfe1e2b1d7db13683599d70ea9fd7dad1e5ff4282af628d3e5e6f1d8feb7e9a
356 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 JavaScript T1204.001 Malicious Link or Macro: Malicious Link

The PDF file contains multiple critical heuristic firings indicating exploitation of CVE-2007-5659 via JavaScript. Specifically, the `Collab.collectEmailInfo` method is used in conjunction with `eval()` and `unescape()` to execute a stager. This stager is designed to download and execute a secondary payload, a common technique for initial access and further infection. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • 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)
  • Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER
    OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
  • ClamAV: Pdf.Exploit.Agent-35912 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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
7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 201 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
annotation_subject_callee_hex_stage_000.js
db9fab039cc75dd554032007ec093b38113e62bd1b9391d93ab194458c7bb573
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5018 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
50eb3d49433508bf251038eaf1c9d77ac87710b8c25054a34b1a7198193d667e
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2B5 11851 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).
deobfuscated.js
67c4a904fd0c9bbc12308522dcd08675326dbffcab28aa47bad3020f2d70dc53
deobfuscated-js PDF JavaScript deobfuscation pass 42443 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).