Questions tagged [code-signing]

Code Signing is the process of putting a signature on executables and patches to prove it is genuine, and to prevent attackers from injecting malicious code into end-user's systems.

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Is signing a file better than issuing a checksum, and does it render a separate checksum useless?

Alternatively, the question could be asked: Does issuing a checksum for a file we sign anyways just duplicate work? Use case: Firmware sent to an IoT device. We sign it, and form a separate checksum ...
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7 votes
1 answer
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How do GPG smart card devices handle large GPG operations?

How do GPG smart card devices (such as a Yubikey) handle large GPG operations? Such as signing binary programs. My first 2 pet theories are: There's some way to chunk up GPG operations or use some ...
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0 votes
1 answer
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Are .NET runtime really not signed?

I'm doing a manual install on Linux of the .NET runtime which can be downloaded from dotnet.microsoft.com. MS do provide a SHA512 checksum of the file on the site, but that can't be use to verify the ...
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1 vote
2 answers
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TPM Endorsement Key usage in secure and trusted boot

Taking into account a Root of Trust in a device using a TPM. My understanding is that the bootloader, firmware, operating system, applications etc. are all verified on startup by validating signatures ...
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6 votes
1 answer
361 views

How can a .exe be modified and still keep a valid digital signature?

When a Windows .exe installer is code-signed, I thought that modifying a single byte (thus changing its SHA256 hash) would make the digital signature invalid, but surprisingly, this is not true. ...
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3 votes
1 answer
337 views

Secure boot after an OTA update confusion

My understanding is that secure boot works by verifying each stage in the boot process before proceeding. So first, UEFI or booting firmware will validate the signature of the bootloader, then kernel, ...
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0 answers
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How To First Strip and Then Sign Kernel Modules at Complie Time

It seems easy to sign kernel modules at compile time. Apparently, you just set CONFIG_MODULE_SIG_ALL=y in your .config file and then the compiler will perhaps give you the appropriate errors until you ...
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0 votes
0 answers
63 views

double hashing for code signing and verification

I have environmental constraints where the cyber and safety functions are segregated such that safety operations are handled by one unit and cyber operations such as firewall, HIDS, secure storage etc....
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0 votes
1 answer
79 views

Why does Microsoft SmartScreen require OV certificates to be signed by a trusted CA?

Signing your applications with an OV code signing certificate enables them to build reputation together in Microsoft SmartScreen, rather than each binary building reputation separately. This allows ...
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What (if any) are the implications of Apple stop signing iOS 15.1?

I have read on the web ([1], [2]) that Apple has stopped signing the iOS 15.1. The two articles describe that it will prevent users from downgrading the OS. And the inability to jailbreak the iPhone. ...
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0 votes
1 answer
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Sharing Yubikey via SSH

I have a MacBook which has a Yubikey. I usually don't use my MacBook for any development. I use a remote Linux server. I would like to sign my commits with Yubikey instead of a gpg key. Can I share my ...
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0 votes
1 answer
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Signing Binaries in CI/CD

I've been considering how continuous integration/delivery environments handle code signing. If I maintain some open source project which uses a CD environment to build binaries to ship to users, I may ...
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1 vote
0 answers
141 views

How to stop 3rd party libraries from being reported as malicious, if they were part of malicious programs in the past?

Some are standard user space dll’s and another one is actually a windows driver. The libraries alone are not dangerous and are pure utilities but they can be used by bad guys, like most software tools....
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1 answer
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designing updater with certificate renewal in mind

A program A downloads signed executables and other signed configuration files. Configuration files have signature appended at the end of files. To verify their integrity and creator, it uses the ...
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1 vote
1 answer
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Software signing : multiple certificates

I'm quite new to the cryptography field, and I'm trying to understand a few things: I used binwalk on Linux to analyse Minecraft.msi, and I found multiple certificates in the .msi See below: I'm ...
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1 vote
1 answer
908 views

How to update certificates/CRL on Windows 7 systems that are without support contracts?

A quality answer to this question mentions: "System is regularly updated with latest patch specifically certificate/CRL from trusted source such as Microsoft." How does one update ...
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0 votes
1 answer
249 views

If a file is digitally signed, is posting a hash very useful for security purposes?

In this question I asked about how to handle situations when SHA-256 hashes are not available for a file downloaded from the internet that contains executable code. Another community member ...
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0 votes
0 answers
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CSP DLLs still needed to be signed?

I'm developing a custom CSP and I want to use it from Adobe Reader but it is not very clear to me if it still needs to be signed because here there is a note: "Starting with Windows 8, it is no ...
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2 votes
1 answer
358 views

What's the difference between an executable signed with a Windows Digital Signature and one signed with PGP?

I'm trying to figure out how to establish trust in Windows executables that I download from the internet. Some software that I download, such as KeepassXC, has a Windows Digital Signature, but they ...
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4 votes
2 answers
351 views

Why should I go to SHA512withRSA signature for my Android apps?

I have an Android 11 device and many of my apps and system apps use MD5withRSA or SHA1withRSA as signature algorithm by default. Why should I take my apps SHA256withRSA or SHA512withRSA? Are there any ...
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0 votes
1 answer
193 views

Spoof publisher info on Windows applications

Let me start by acknowledging that I have absolutely no experience with Windows development and this is purely for academic purposes. I apologize for incorrect terminology and welcome corrections or ...
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1 vote
0 answers
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Is it ok to store my Android app keystore password in a text file on my disk?

I am reading on how to sign and publish my flutter app on android. When reading through the official docs, they suggest to make a configuration file where I put my password to the keystore in plain ...
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1 vote
0 answers
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Standard for verifying certificates that signed code

When one verifies a certificate that came alongside a signature for some sort of code, is there a standard that specifies what shall be verified? For example, if I'm to verify a certificate that came ...
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0 votes
0 answers
79 views

Switching CSC certificate issuer and SmartScreen

We have most of our SSL certificates hosted at GoDaddy but have Standard Code signing certificate from GlobalSign, we would like to switch to GoDaddy CSC since our CSC from GlobalSign is expiring in 3 ...
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1 vote
1 answer
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Which practices should i use while generating SMS codes for auth on my project?

Let's imagine that we have an SMS verification auth, and using random 4-digit codes, i.e. 1234, 5925, 1342 and etc. I'm using this random inclusive algorithm on my node.js server: function ...
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4 votes
1 answer
295 views

How to validate client side safety in a Zero Knowlegde model

What is sometimes called Zero Knowledge, sometimes end to end encryption occurs when a server only processes ciphered data (at least for sensitive data) with a result where a compromise of this server ...
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1 vote
2 answers
232 views

Why infamous Addtrust certificate is still not expired (same private key) for code signing?

As many of you know Addtrust certificate https://crt.sh/?id=1 expired 30 May 2020 as well as many other intermediate certs and now we have to update certs on many servers to either root cert https://...
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0 votes
2 answers
286 views

How can we verify an installer's validity by checking its signature?

I'm working on some software that can be self-hosted, and it includes a component that can be downloaded and installed on end user machines (Windows only). The download comes from the self-hosted ...
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7 votes
1 answer
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gpg key size of 4096 and "the future is ECC"

My boss wants to sign our binary. I need to tell him how he can create the signing key. Most if not all sites I have seen about signing binaries say "use gpg". OK, so gpg per default has 2048. Their ...
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2 votes
1 answer
6k views

How to verify a GPG file signature on Linux and Windows without connecting to the Internet?

Can you please hint me to the steps I need to verify a file's signature (without connecting to the Internet) on command line using GnuPG, when I have the required files ready: -installation file (eg ...
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0 votes
1 answer
194 views

File authentifications via PGP versus via unique file hashes

Many files that are available for download (eg in github) come along with "asc" signature files attached, or with a sha256 file hash. Can someone please explain difference of PGP signatures vs file ...
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1 vote
0 answers
85 views

Create signed release binaries and distribute with custom repository (debian)

I have been tasked to create a custom repository with signed binaries for download. Our CEO explicitly mentioned that he wants the binary signed by himself and his business parther. I set up a ...
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3 votes
1 answer
165 views

Why does Windows consider a certificate valid even after its expiration time?

I downloaded Google's Cloud SDK installer today, and upon checking the certificate to validate it, I noticed something strange: the expiration date of the certificate appears to be December 22nd 2019 -...
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1 vote
1 answer
348 views

Why does productsign use SHA1 instead of SHA256 to sign the pkg?

I have an application which is packed into a pkg file using productbuild and then is signed using productsign. However when I run pkgutil --check-signature only the SHA1 signature is shown. I also ...
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1 vote
2 answers
415 views

Can I use Let's Encrypt to verify my signing key?

I've made a signing key with GPG and I would like to have it verified since GPG displays a warning whenever a file signed with my key is verified. I've heard of Let's Encrypt but it only talks about ...
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1 vote
0 answers
158 views

Confirming the validity/ownership of a Android Signing Certificate

I have a certificate that says the application was signed by Google, but on multiple searches I have reason to believe that it's not actually a google signing certificate. Is there a way to query ...
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1 vote
0 answers
102 views

Can an EXE code signing renew even though it's expired?

I've just downloaded composer from getcomposer.org, but a strange thing had happened. When I clicked "install for all users" button, the UCA says "Unknown publisher", but when I was checking its ...
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0 votes
1 answer
149 views

Cryptographically signing content / download

Let's say that I have an executable running on a client machine, and, it requires to download some updates on a regular basis. The solution uses TLS to communicate with the download server. I would ...
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2 votes
1 answer
386 views

How to ensure authenticity and integrity of a directory

I want to do something similar to Ubuntu's signed checksums in distribution and I'm currently stuck on the integrity part. The tutorial here covers most of what I'd like the process to look like (I've ...
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0 votes
0 answers
196 views

Check CRLs of signed JARs

I have a signed JAR. How could I check if the corresponding code-signing certificate was revoked? Technically there seem to be the following options: The Java TrustStore holds CRLs/revoked ...
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  • 600
21 votes
3 answers
6k views

Transferring Microsoft SmartScreen reputation to renewed certificate

I know that even a software signed with a new code signing certificate triggers Microsoft Defender SmartScreen warning: Windows Defender SmartScreen prevented an unrecognized app from starting The ...
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1 vote
0 answers
86 views

How attackers bypass windows smart screen [closed]

I'm curious to how attackers gain access to valid EV certificates that bypass windows smart screen (for malware delivery/execution) or how they sign these malicious software(s) without access to EV ...
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3 votes
1 answer
457 views

How reliable is Virustotal's file signature check?

I downloaded a setup.msi file from an untrusted website. Virustotal says it's a signed file and valid signature, by the developer company and "GlobalSign Extended Validation CodeSigning CA" 3 times ...
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1 vote
0 answers
87 views

What does jarsigner verify in the first place (integrity or authenticity)?

I was reading sth about android code signing and have run into this statement: The second jarsigner command at v in Listing 3-7 first verifies the signature block and signing certificate, ...
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1 vote
0 answers
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High Availability Boot processes and only using code-signing certificates

High Availability Boot (HAB) is a technique described here in an NxP application note. This is best summarised as: "HAB authentication is based on public key cryptography using the RSA algorithm in ...
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  • 123
0 votes
1 answer
250 views

Cross-signing certificates for Windows Driver Signing

For testing purposes I want to test cross-signing certificates for Windows driver signing. I understand the general concept: Two root CAs, one root CA cross-signs the other root CA's public key. ...
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  • 600
5 votes
1 answer
573 views

Having a code-signed binary, how can I tell if it's signed with an Extended Validation (EV) certificate?

I can't seem to find an answer to this seemingly simple question. Say, on Windows, if I have a binary file: How can I tell if it was signed with an extended validation (EV) code-signing certificate? ...
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  • 171
1 vote
0 answers
137 views

Certificate pinning for device firmware signing

What are common mechanisms to ensure that a device firmware is not only properly signed, but actually signed by the correct device manufacturer? In TLS communications, certificate pinning or public ...
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  • 11
5 votes
3 answers
2k views

Why are non-collision-resistant hash functions considered insecure for signing self-generated information

Let we have a hash function that is second preimage resistant but not collision-resistant. Then an adversary can create a pair of different messages M and M', M is benign and M' is malicious, for ...
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0 votes
2 answers
128 views

Signing the same solution (list of files) by multiple CA

We (platform owner) have a requirement to sign a 3rd party (partner) software solution which will be hosted on our platform. The 3rd party solution is signed by the partner with some well known CA. ...
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