https://freemyipod.org/api.php?action=feedcontributions&feedformat=atom&user=TISFMiP 2026-04-09T07:11:59Z User contributions MediaWiki 1.45.1 https://freemyipod.org/index.php?title=ByteFau1t&diff=22176 2025-12-01T03:19:17Z

<p>TISFMiP: Article about the new vulnerability ByteFau1t</p> <hr /> <div>== ByteFau1t Vulnerability ==<br /> {{DISPLAYTITLE:ByteFau1t}}<br /> <br /> ByteFau1t is a flaw in the IMG1 partition-type handling logic inside the SecureROM of the<br /> iPod nano (7th generation). The bug causes the integrity verification step for certain<br /> IMG1 images to be skipped, allowing modified data inside the rsrc partition to load<br /> without any signature checks.<br /> <br /> The issue was discovered by Fong and publicly disclosed on 30 June 2025.<br /> <br /> === Affected Devices ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> |-<br /> ! Device !! Vulnerable? !! Notes<br /> |-<br /> | iPod nano 7G (2012) || Yes || Verified working<br /> |-<br /> | iPod nano 7G (rev A)(2015) || Yes || Same SecureROM code path<br /> |-<br /> | iPod nano 6G || ? || Early tests suggest it does not work<br /> |-<br /> | Other S5L-based devices || Unknown || No confirmed evidence<br /> |}<br /> <br /> === Summary ===<br /> <br /> The vulnerability is triggered by modifying the *format byte* inside the IMG1 header<br /> stored within the rsrc partition. Inside the IPSW, this byte is found in the MSE file.<br /> There is only one instance of the signature:<br /> <br /> 38 37 34 30 32 2E 30 04<br /> <br /> The final byte (04) represents an *unencrypted + signed* IMG1 image.<br /> Changing it to 03 marks the image as *encrypted + signed*.<br /> <br /> When SecureROM processes an IMG1 image marked as encrypted (03) but whose contents are<br /> actually unencrypted, it enters an alternative decryption-handling path. This path has<br /> an unhandled condition for unencrypted data, causing the entire integrity verification<br /> step to be skipped. As a result, SecureROM accepts and loads modified IMG1 data as if<br /> it were valid.<br /> <br /> === What ByteFau1t Allows ===<br /> <br /> * Modification of rsrc contents without using any previous untethered exploits And it doesn't require pressing any buttons.<br /> <br /> ByteFau1t does **not** provide full SecureROM code execution, but it enables UI<br /> customization, resource patching, and limited modification of system content embedded<br /> in rsrc.<br /> <br /> === Technical Details ===<br /> <br /> * The MSE file holds multiple IMG1 headers<br /> * The format byte determines the SecureROM decryption/verification path<br /> * The “encrypted + signed” path (03) expects a specific internal decoder state<br /> * Feeding unencrypted data into this path results in an inconsistent state<br /> * In this state, the final cryptographic integrity check is skipped entirely<br /> * SecureROM proceeds as though the image were verified<br /> <br /> This is a logic flaw, not a memory-corruption vulnerability.<br /> <br /> === Status / Fix ===<br /> <br /> {| class=&quot;wikitable&quot;<br /> |-<br /> ! Property !! Value<br /> |-<br /> | Fixed in || Not fixed<br /> |-<br /> | Patched devices || None<br /> |-<br /> | Discovered by || Fong<br /> |-<br /> | Disclosed || 30 June 2025<br /> |}<br /> <br /> === Nano 6G Possibility ===<br /> <br /> Attempts to apply the method to the iPod nano 6G were unsuccessful.<br /> Nano 6 SecureROM uses a probably different circuit.<br /> Current research status: incompatible.</div>

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