Yubico-Piv 1.5.0 Error lib/ykpiv.c ykpiv_transfer_data` out-of-bounds write

Summaryinfo

A vulnerability categorized as critical has been discovered in Yubico-Piv 1.5.0. This impacts the function ykpiv_transfer_data` in the library lib/ykpiv.c of the component Error Handler. Executing a manipulation can lead to out-of-bounds write. This vulnerability is handled as CVE-2018-14779. The physical device can be targeted for the attack. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Yubico-Piv 1.5.0. It has been declared as critical. This vulnerability affects the function ykpiv_transfer_data` in the library lib/ykpiv.c of the component Error Handler. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A buffer overflow issue was discovered in the Yubico-Piv 1.5.0 smartcard driver. The file lib/ykpiv.c contains the following code in the function `ykpiv_transfer_data()`: {% highlight c %} if(*out_len + recv_len - 2 > max_out) { fprintf(stderr, "Output buffer to small, wanted to write %lu, max was %lu.", *out_len + recv_len - 2, max_out); } if(out_data) { memcpy(out_data, data, recv_len - 2); out_data += recv_len - 2; *out_len += 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.

The bug was discovered 08/14/2018. The weakness was released 08/15/2018 (oss-sec). The advisory is shared for download at openwall.com. This vulnerability was named CVE-2018-14779 since 08/01/2018. The exploitation appears to be easy. The attack needs to be approached locally. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 1 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 117329 (openSUSE Security Update : yubico-piv-tool (openSUSE-2018-969)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 171555 (OpenSUSE Security Update for yubico-piv-tool (openSUSE-SU-2018:2623-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (117329). Entry connected to this vulnerability is available at VDB-122957. Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• Yubico-Piv

Version

• 1.5.0

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Once again VulDB remains the best source for vulnerability data.

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