Rainer Gerhards

4 exploits Active since Mar 2018
CVE-2019-17041 NOMISEC CRITICAL WORKING POC
Rsyslog - Out-of-Bounds Write
An issue was discovered in Rsyslog v8.1908.0. contrib/pmaixforwardedfrom/pmaixforwardedfrom.c has a heap overflow in the parser for AIX log messages. The parser tries to locate a log message delimiter (in this case, a space or a colon) but fails to account for strings that do not satisfy this constraint. If the string does not match, then the variable lenMsg will reach the value zero and will skip the sanity check that detects invalid log messages. The message will then be considered valid, and the parser will eat up the nonexistent colon delimiter. In doing so, it will decrement lenMsg, a signed integer, whose value was zero and now becomes minus one. The following step in the parser is to shift left the contents of the message. To do this, it will call memmove with the right pointers to the target and destination strings, but the lenMsg will now be interpreted as a huge value, causing a heap overflow.
CVSS 9.8
CVE-2018-1000140 NOMISEC CRITICAL WORKING POC
rsyslog librelp <1.2.14 - Buffer Overflow
rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can connect to rsyslog and trigger a stack buffer overflow by sending a specially crafted x509 certificate.
CVSS 9.8
CVE-2018-1000140 NOMISEC CRITICAL WORKING POC
rsyslog librelp <1.2.14 - Buffer Overflow
rsyslog librelp version 1.2.14 and earlier contains a Buffer Overflow vulnerability in the checking of x509 certificates from a peer that can result in Remote code execution. This attack appear to be exploitable a remote attacker that can connect to rsyslog and trigger a stack buffer overflow by sending a specially crafted x509 certificate.
CVSS 9.8
CVE-2022-24903 WRITEUP HIGH WRITEUP
Rsyslog < 8.2204.1 - Remote Code Execution
Rsyslog is a rocket-fast system for log processing. Modules for TCP syslog reception have a potential heap buffer overflow when octet-counted framing is used. This can result in a segfault or some other malfunction. As of our understanding, this vulnerability can not be used for remote code execution. But there may still be a slight chance for experts to do that. The bug occurs when the octet count is read. While there is a check for the maximum number of octets, digits are written to a heap buffer even when the octet count is over the maximum, This can be used to overrun the memory buffer. However, once the sequence of digits stop, no additional characters can be added to the buffer. In our opinion, this makes remote exploits impossible or at least highly complex. Octet-counted framing is one of two potential framing modes. It is relatively uncommon, but enabled by default on receivers. Modules `imtcp`, `imptcp`, `imgssapi`, and `imhttp` are used for regular syslog message reception. It is best practice not to directly expose them to the public. When this practice is followed, the risk is considerably lower. Module `imdiag` is a diagnostics module primarily intended for testbench runs. We do not expect it to be present on any production installation. Octet-counted framing is not very common. Usually, it needs to be specifically enabled at senders. If users do not need it, they can turn it off for the most important modules. This will mitigate the vulnerability.
CVSS 8.1