-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 X41 D-Sec GmbH Security Advisory: X41-2018-001
Multiple Vulnerabilities in Yubico Piv ====================================== Overview - -------- Confirmed Affected Versions: 1.5.0 Confirmed Patched Versions: 1.6.0 Vendor: Yubico Vendor URL: https://www.yubico.com/ Vendor Advisory URL: https://www.yubico.com/support/security-advisories Credit: X41 D-Sec GmbH, Eric Sesterhenn Status: Public Advisory-URL: https://www.x41-dsec.de/lab/advisories/x41-2018-001-Yubico-Piv/ Summary and Impact - ------------------ A buffer overflow and an out of bounds memory read were identified in the yubico-piv-tool-1.5.0, these can be triggered by a malicious token. X41 did not perform a full test or audit on the software. Product Description - ------------------- YubiKey 4, YubiKey 4 Nano, YubiKey 4C, YubiKey 4C Nano, and YubiKey NEO provide Smart Card functionality based on the Personal Identity Verification (PIV) interface specified in NIST SP 800-73, “Cryptographic Algorithms and Key Sizes for PIV.” Out of Bounds Write via Malicious APDU ====================================== Severity Rating: High Vector: APDU Response CVE: CVE-2018-14779 CWE: 120 CVSS Score: 7.1 (High) CVSS Vector: CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H Summary and Impact - ------------------ File lib/ykpiv.c contains the following code in function ykpiv_transfer_data() {% highlight c %} if(*outlen + recvlen - 2 > maxout) { fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *outlen + recvlen - 2, maxout); } if(outdata) { memcpy(outdata, data, recvlen - 2); outdata += recvlen - 2; *outlen += recv_len - 2; } {% endhighlight %} It is clearly checked whether the buffer is big enough to hold the data copied using memcpy(), but no error handling happens to avoid the memcpy() in such cases. This code path can be triggered with malicious data coming from a smartcard. Workarounds - ----------- None Out of Bounds Read via malicious APDU ===================================== Severity Rating: LOW Vector: APDU Response CVE: CVE-2018-14780 CWE: 125 CVSS Score: 2.2 (Low) CVSS Vector: CVSS:3.0/AV:P/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N Summary and Impact - ------------------ File lib/ykpiv.c contains the following code in function _ykpiv_fetch_object() {% highlight c %} if(sw == SWSUCCESS) { sizet outlen; int offs = ykpivgetlength(data + 1, &outlen); if(offs == 0) { return YKPIVSIZEERROR; } memmove(data, data + 1 + offs, outlen); *len = outlen; return YKPIVOK; } else { return YKPIVGENERICERROR; } {% endhighlight %} In the end, a memmove() occurs with a length retrieved from APDU data. This length is not checked if it is outside of the APDU data retrieved. Therefore the memmove() could copy bytes behind the allocated data buffer into this buffer. Workarounds - ----------- None Timeline ======== 2018-02-03 Issues found 2018-05-22 Vendor contacted 2018-05-22 Vendor reply 2018-06-05 Requesting technical feedback from the vendor 2018-06-06 Vendor confirms bug 2018-08-01 CVE ID requested 2018-08-02 CVE ID assigned 2018-08-08 Patched version released by vendor 2018-08-11 Advisory released -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEpwxVTgxAIcUvTugIo5Klpg50CxAFAlty2y4ACgkQo5Klpg50 CxAwehAAqTUuKo2ewJ90g6HTtWvEGc+2NkLMNYM/Tv8bKbCg8g6XupPSXSUq1iCK +2kyg4RSjd2G3aufXVVp/SRIHseO2ZZV1kgp3YXtOdj6T5rs/FXrUdkS3J8CQAaL 7VBnM+lEWM0TeK+3Bc4x36W5ht5Qmq76hUQNQTfj1gtgd608TYjpDcWCupPAf9Rf E5axwUoSA+pZIWWdrRO7DZYb6600FuOvlsxLJYlRVqb2rZSaLnePtCIogvpZfz6Y 4LzQ7AFZ5X+/U9BsSVrZY82xTkPIKVgt46aiH5oOa+3uw1rgpY1dHZUf+tgOdRms 5goHGzRgQLxwHmY1zoqOCRHSKR6ChxUdMeI3TOmW1MiTAaW6WTIeDzwX15nYyZ5P s8fUefaUK7PUOgnJgKbCuPCOWpoAuALF0EVJ/Hq3UP+fDxnOMp7IHyW4B41v15zx HIJBTpz2G9Th6B4bufsv9nTOVhAMzUFCf2kR21jpOrqLGH9qnC0OqqTYqdeQfujh p6RH775F4uqxT95YMR7ISuagv6WMdgHaOrOEWvsB/bhj7IiAhvQ03R2Q3462Iqgd O6w4YMoASyYn3l6ZTXL0Jmr4jXsEmY2UnNJyrHLZvpWXRENVHgX9TdsvWgI1F5vz 7vIizz1PXXDug2D6g61O6NKUALpH0bBqVEuc0MxG8KRv9L67S2Q= =zPb1 -----END PGP SIGNATURE----- _______________________________________________ Sent through the Full Disclosure mailing list https://nmap.org/mailman/listinfo/fulldisclosure Web Archives & RSS: http://seclists.org/fulldisclosure/