Rating:
### rdctd 1
**Challenge Description**:
Analyze a PDF document to find the flag containing the digit `1`.
**Analysis**:
The PDF `Planned-Flags-signed-2.pdf` contains several flags in different states of redaction. By searching the uncompressed PDF streams, we found:
- An unredacted flag in Section 3.4: `ENO{stability_gradient_1_disrupted}`.
**Flag**:
`ENO{stability_gradient_1_disrupted}`
### rdctd 2
**Challenge Description**:
Analyze same PDF document to find the flag containing the digit `2`.
**Analysis**:
Searching the uncompressed PDF revealed URI annotations (links) that contained a flag:
- `https://ctf.nullcon.net/ENO{input_sanitization_2_is_overrated}`
**Flag**:
`ENO{input_sanitization_2_is_overrated}`
### rdctd_3
**Challenge Description**:
Analyze an image `image-000.png` extracted from the PDF to find the flag containing the digit `3`.
**Analysis**:
The image contains blurred text which was identified as `ENO{semantic_3_inference_initialized}`. This flag fits the pattern and contains the digit `3`.
**Flag**: `ENO{semantic_3_inference_initialized}`
### rdctd_4
**Challenge Description**:
Analyze the PDF to find the flag containing the digit `4`.
**Analysis**:
The PDF contained a hidden QR code. Scanning the QR code revealed the flag.
**Flag**: `ENO{We_should_have_an_Ontology_to_4_categorize_our_ontologies}`
### rdctd_5
**Challenge Description**:
Analyze the PDF to find the flag containing the digit `5`.
**Analysis**:
Iterating through all objects in the PDF's cross-reference table (xref) and searching for the string format `ENO{...}` revealed the flag hidden within a raw object.
**Flag**: `ENO{SIGN_HERE_TO_GET_ALL_FLAGS_5}`
### rdctd 6
**Challenge Description**:
Analyze same PDF document to find the flag containing the digit `6`.
**Analysis**:
Inspecting the PDF metadata using `exiftool` revealed a flag in the `Producer` field which contains the digit `6` (as part of `76`):
- `ENO{secureflaghidingsystem76}`
**Flag**:
`ENO{secureflaghidingsystem76}`
