CVE-2018-20022

LibVNC before 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838 contains multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allows attacker to read stack memory and can be abuse for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and in bypassing ASLR

Weakness

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, in Java, if the programmer does not explicitly initialize a variable, then the code could produce a compile-time error (if the variable is local) or automatically initialize the variable to the default value for the variable’s type. In Perl, if explicit initialization is not performed, then a default value of undef is assigned, which is interpreted as 0, false, or an equivalent value depending on the context in which the variable is accessed.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/29.html

References

• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-032-libvnc-multiple-memory-leaks/
• https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html
• https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
• https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html
• https://lists.debian.org/debian-lts-announce/2019/12/msg00028.html
• https://security.gentoo.org/glsa/201908-05
• https://security.gentoo.org/glsa/202006-06
• https://usn.ubuntu.com/3877-1/
• https://usn.ubuntu.com/4547-1/
• https://usn.ubuntu.com/4547-2/
• https://usn.ubuntu.com/4587-1/
• https://www.debian.org/security/2019/dsa-4383