The vulnerability is in the library’s logging function, which is coded in the C language. musl is also C (afaik), it’s just a more modern, safer rewrite of libc.
I’m not sure what you mean by a “vulnerability in the logs”. In a logger or parser, sure, but did you think text data at rest was able to reach out and attack your system?
True, the logging is part of the library, but it’s totally centered on what the developers are logging. It’s a bad practice to log sensitive information, which can be used by someone with access to the logs for sure, but that doesn’t mean the library is broken and has to be replaced. The library’s logs need to be audited, and this as true for glibc as it is for musl, no exception, and it’s not a one time thing, since as the libraries evolve, sensitive information can be introduced unintentionally (perhaps debugging something required it on some particular testing, and it was forgotten there).
BTW, what I meant with the language, is that no matter the language, you might unintentionally allow some sensitive information in the logs, because that’s not a syntactic error, and it’s not violating any compiling rules. It’s that something is logged that shouldn’t.
Also, the report indicates that the vulnerability can’t be exploited remotely, which reduces the risk for several systems…
The vulnerability has nothing to do with accidentally logging sensitive information, but crafting a special payload to be logged which gets glibc to write memory it isn’t supposed to write into because it didn’t allocate memory properly. glibc goes too far outside of the scope of its allocation and writes into other memory regions, which an attacked could carefully hand craft to look how they want.
Other languages wouldn’t have this issue because
they wouldn’t willy nilly allocate a pointer directly like this, but rather make a safer abstraction type on top (like a C++ vector), and
they’d have bounds checking when the compiler can’t prove you can go outside of valid memory regions. (Manually calling .at() in C++, or even better - using a language like rust which makes bounds checks default and unchecked access be opt in with a special method).
Edit: C’s bad security is well known - it’s the primary motivator for introducing rust into the kernel. Google / Microsoft both report 70% of their security vulnerabilities come from C specific issues, curl maintainer talks about how they use different sanitizers and best practices and still run into the same issues, and even ubiquitous and security critical libraries and tools like sudo + polkit suffer from them regularly.
I see, I didn’t dig into the cause, being sort of a buffer overflow. Indeed that would be prevented by other languages, sorry for my misinterpretation. Other vulnerabilities unintentionally introduced by developers on logging what shouldn’t are not dependent on anything other than auditing them, but that was not the case then.
The vulnerability is in the library’s logging function, which is coded in the C language. musl is also C (afaik), it’s just a more modern, safer rewrite of libc.
I’m not sure what you mean by a “vulnerability in the logs”. In a logger or parser, sure, but did you think text data at rest was able to reach out and attack your system?
True, the logging is part of the library, but it’s totally centered on what the developers are logging. It’s a bad practice to log sensitive information, which can be used by someone with access to the logs for sure, but that doesn’t mean the library is broken and has to be replaced. The library’s logs need to be audited, and this as true for glibc as it is for musl, no exception, and it’s not a one time thing, since as the libraries evolve, sensitive information can be introduced unintentionally (perhaps debugging something required it on some particular testing, and it was forgotten there).
BTW, what I meant with the language, is that no matter the language, you might unintentionally allow some sensitive information in the logs, because that’s not a syntactic error, and it’s not violating any compiling rules. It’s that something is logged that shouldn’t.
Also, the report indicates that the vulnerability can’t be exploited remotely, which reduces the risk for several systems…
The vulnerability has nothing to do with accidentally logging sensitive information, but crafting a special payload to be logged which gets glibc to write memory it isn’t supposed to write into because it didn’t allocate memory properly. glibc goes too far outside of the scope of its allocation and writes into other memory regions, which an attacked could carefully hand craft to look how they want.
Other languages wouldn’t have this issue because
they wouldn’t willy nilly allocate a pointer directly like this, but rather make a safer abstraction type on top (like a C++ vector), and
they’d have bounds checking when the compiler can’t prove you can go outside of valid memory regions. (Manually calling .at() in C++, or even better - using a language like rust which makes bounds checks default and unchecked access be opt in with a special method).
Edit: C’s bad security is well known - it’s the primary motivator for introducing rust into the kernel. Google / Microsoft both report 70% of their security vulnerabilities come from C specific issues, curl maintainer talks about how they use different sanitizers and best practices and still run into the same issues, and even ubiquitous and security critical libraries and tools like sudo + polkit suffer from them regularly.
I see, I didn’t dig into the cause, being sort of a buffer overflow. Indeed that would be prevented by other languages, sorry for my misinterpretation. Other vulnerabilities unintentionally introduced by developers on logging what shouldn’t are not dependent on anything other than auditing them, but that was not the case then.