SB2021050639 - Ubuntu update for exim4
Published: May 6, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 16 secuirty vulnerabilities.
1) UNIX symbolic link following (CVE-ID: CVE-2020-28007)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a symlink following issue in Exim log directory. A local user can create a specially crafted symbolic link to a critical file on the system and overwrite it with privileges of the application.
Successful exploitation of this vulnerability may result in privilege escalation.
2) Security restrictions bypass (CVE-ID: CVE-2020-28008)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to application does not properly impose security restrictions on the spool directory. A local user can escalate privileges on the system.
3) Integer overflow (CVE-ID: CVE-2020-28009)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to integer overflow in get_stdinput() function. A local user can execute arbitrary code with elevated privileges.
4) Heap-based buffer overflow (CVE-ID: CVE-2020-28011)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error in queue_run() function. A local user can trigger heap-based buffer overflow and execute arbitrary code with elevated privileges.
5) Security features bypass (CVE-ID: CVE-2020-28012)
The vulnerability allows a local user to bypass implemented security restrictions.
The vulnerability exists due to missing close-on-exec flag for privileged pipe. A local user can escalate privileges on the system.
6) Heap-based buffer overflow (CVE-ID: CVE-2020-28013)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error in parse_fix_phrase() function. A local user can trigger heap-based buffer overflow and execute arbitrary code with elevated privileges.
7) Security restrictins bypass (CVE-ID: CVE-2020-28014)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to application uses PID files in an insecure manner. A local user can predict the name of the PID file and use it to escalate privileges on the system.
8) Input validation error (CVE-ID: CVE-2020-28015)
The vulnerability allows a local user to bypass implemented security restrictions
The vulnerability exists due to insufficient validation of user-supplied input when processing new line characters. A local user can inject a new line character into spool header file and execute arbitrary commands.
9) Out-of-bounds write (CVE-ID: CVE-2020-28016)
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a boundary error within the parse_fix_phrase() function. A local user can trigger an out-of-bounds write and execute arbitrary code on the target system with elevated privileges.
10) Integer overflow (CVE-ID: CVE-2020-28017)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer overflow within the receive_add_recipient() function. A remote attacker can pass specially crafted data to the application, trigger integer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
11) Integer overflow (CVE-ID: CVE-2020-28020)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer overflow in receive_msg() function. A remote non-authenticated attacker can send specially crafted data to the mail server, trigger integer overflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
12) Out-of-bounds write (CVE-ID: CVE-2020-28022)
The vulnerability allows a remote attacker to compromise vulnerable system.
The vulnerability exists due to a boundary error when processing untrusted input within the extract_option() function. A remote attacker can create a specially crafted message to the mail server, trigger and out-of-bounds write or read error and execute arbitrary code on the target system.
13) Integer underflow (CVE-ID: CVE-2020-28024)
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to integer underflow in smtp_ungetc() function. A remote attacker can send a specially crafted data to the application, trigger integer underflow and execute arbitrary code on the target system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
14) Out-of-bounds read (CVE-ID: CVE-2020-28025)
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition in pdkim_finish_bodyhash() function. A remote attacker can trigger out-of-bounds read error and read contents of memory on the system.
15) Input validation error (CVE-ID: CVE-2020-28026)
The vulnerability allows a remote attacker to bypass implemented security restrictions
The vulnerability exists due to insufficient validation of user-supplied input in the spool_read_header() function. A remote attacker can inject lines and manipulate mail queue.
16) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2021-27216)
The vulnerability allows a local user to delete arbitrary files on the system.
The vulnerability exists due to application does not properly impose security restrictions. A local user can delete arbitrary files on the system.
Remediation
Install update from vendor's website.