The Int.Exp Montgomery code in the math/big library in Go 1.5.x before 1.5.3 mishandles carry propagation and produces incorrect output, which makes it easier for attackers to obtain private RSA keys via unspecified vectors.

This go update to version 1.6 fixes the following issues :

Security issues fixed :

  - CVE-2016-3959: Infinite loop in several big integer     routines (boo#974232)

  - CVE-2015-8618: Carry propagation in Int.Exp Montgomery     code in math/big library (boo#960151)

Bugs fixed :

  - Update to version 1.6 :

  - On Linux on little-endian 64-bit PowerPC     (linux/ppc64le), Go 1.6 now supports cgo with external     linking and is roughly feature complete.

  - Vendoring support

  - HTTP2 transparent support

  - fix gc and gccgo incompatibility regarding embedded     unexported struct types containing exported fields

  - Linux on 64-bit MIPS and Android on 32-bit x86

  - enforced rules for sharing Go pointers with C

  - new mechanism for template reuse

  - performance improvements ... and more! see more in     https://tip.golang.org/doc/go1.6 

  - Updated to version 1.5.2: This release includes bug     fixes to the compiler, linker, and the mime/multipart,     net, and runtime packages.
    https://golang.org/doc/devel/release.html#go1.5.minor

  - Updated to version 1.5.1: &#9;This release includes bug     fixes to the go command, the compiler, assembler, and     the fmt, net/textproto, net/http, and runtime packages.
    https://golang.org/doc/devel/release.html#go1.5.minor

  - Update to version 1.5 :

  - see https://golang.org/doc/go1.5 

  - install shared stdlib on x86_64

  - add go.gdbinit for debug friendly

  - Adapt to Leap

  - use gcc5-go than go1.4 is the proper requirement for     Leap

- Rebase to 1.5.3 - Security fix for CVE-2015-8618

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

Jason Buberel reports :

A security-related issue has been reported in Go's math/big package.
The issue was introduced in Go 1.5. We recommend that all users upgrade to Go 1.5.3, which fixes the issue. Go programs must be recompiled with Go 1.5.3 in order to receive the fix.

The Go team would like to thank Nick Craig-Wood for identifying the issue.

This issue can affect RSA computations in crypto/rsa, which is used by crypto/tls. TLS servers on 32-bit systems could plausibly leak their RSA private key due to this issue. Other protocol implementations that create many RSA signatures could also be impacted in the same way.

Specifically, incorrect results in one part of the RSA Chinese Remainder computation can cause the result to be incorrect in such a way that it leaks one of the primes. While RSA blinding should prevent an attacker from crafting specific inputs that trigger the bug, on 32-bit systems the bug can be expected to occur at random around one in 2^26 times. Thus collecting around 64 million signatures (of known data) from an affected server should be enough to extract the private key used.

On 64-bit systems, the frequency of the bug is so low (less than one in 2^50) that it would be very difficult to exploit. Nonetheless, everyone is strongly encouraged to upgrade.

ID	Name	Product	Family	Severity
91276	openSUSE Security Update : go (openSUSE-2016-606)	Nessus	SuSE Local Security Checks	high
89550	Fedora 23 : golang-1.5.3-1.fc23 (2016-5a073cbd93)	Nessus	Fedora Local Security Checks	high
89504	Fedora 22 : golang-1.5.3-1.fc22 (2016-2dcc094217)	Nessus	Fedora Local Security Checks	high
87983	FreeBSD : go -- information disclosure vulnerability (6809c6db-bdeb-11e5-b5fe-002590263bf5)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2015-8618

high

Tenable Plugins

high

high

high

high