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ClamD: Disable VirusEvent '%f' feature, use environment var instead

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The '%f' filename format character has been disabled and will no longer
be replaced with the file name, due to command injection security concerns.
Use the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead.

For the same reason, you should NOT use the environment variables in the
command directly, but should use it carefully from your executed script.
This commit is contained in:
Micah Snyder 2024-01-10 12:09:15 -05:00
parent 2b55c15b8c
commit 2f6b71eb98
5 changed files with 38 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

8
clamd/clamd_others.c
View file

@ -101,6 +101,8 @@ void virusaction(const char *filename, const char *virname,
#define VE_FILENAME "CLAM_VIRUSEVENT_FILENAME"
#define VE_VIRUSNAME "CLAM_VIRUSEVENT_VIRUSNAME"
#define FILENAME_DISABLED_MESSAGE "The filename format character has been disabled due to security concerns, use the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead."
void virusaction(const char *filename, const char *virname,
const struct optstruct *opts)
{
@ -145,7 +147,7 @@ void virusaction(const char *filename, const char *virname,
}
len = strlen(opt->strarg);
buffer_cmd =
(char *)calloc(len + v * strlen(virname) + f * strlen(filename) + 1, sizeof(char));
(char *)calloc(len + v * strlen(virname) + f * strlen(FILENAME_DISABLED_MESSAGE) + 1, sizeof(char));
if (!buffer_cmd) {
if (path)
xfree(env[0]);
@ -160,8 +162,8 @@ void virusaction(const char *filename, const char *virname,
j += strlen(virname);
i++;
} else if (i + 1 < len && opt->strarg[i] == '%' && opt->strarg[i + 1] == 'f') {
strcat(buffer_cmd, filename);
j += strlen(filename);
strcat(buffer_cmd, FILENAME_DISABLED_MESSAGE);
j += strlen(FILENAME_DISABLED_MESSAGE);
i++;
} else {
buffer_cmd[j++] = opt->strarg[i];

2
common/optparser.c
View file

@ -337,7 +337,7 @@ const struct clam_option __clam_options[] = {
{"DisableCache", "disable-cache", 0, CLOPT_TYPE_BOOL, MATCH_BOOL, 0, NULL, 0, OPT_CLAMD | OPT_CLAMSCAN, "This option allows you to disable clamd's caching feature.", "no"},
{"VirusEvent", NULL, 0, CLOPT_TYPE_STRING, NULL, -1, NULL, 0, OPT_CLAMD, "Execute a command when a virus is found. In the command string %v will be\nreplaced with the virus name and %f will be replaced with the file name.\nAdditionally, two environment variables will be defined: $CLAM_VIRUSEVENT_FILENAME\nand $CLAM_VIRUSEVENT_VIRUSNAME.", "/usr/bin/mailx -s \"ClamAV VIRUS ALERT: %v\" alert < /dev/null"},
{"VirusEvent", NULL, 0, CLOPT_TYPE_STRING, NULL, -1, NULL, 0, OPT_CLAMD, "Execute a command when virus is found.\nUse the following environment variables to identify the file and virus names:\n- $CLAM_VIRUSEVENT_FILENAME\n- $CLAM_VIRUSEVENT_VIRUSNAME\nIn the command string, '%v' will also be replaced with the virus name.\nNote: The '%f' filename format character has been disabled and will no longer\nbe replaced with the file name, due to command injection security concerns.\nUse the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead.\nFor the same reason, you should NOT use the environment variables in the\ncommand directly, but should use it carefully from your executed script.", "/opt/send_virus_alert_sms.sh"},
{"ExitOnOOM", NULL, 0, CLOPT_TYPE_BOOL, MATCH_BOOL, 0, NULL, 0, OPT_CLAMD, "Stop the daemon when libclamav reports an out of memory condition.", "yes"},

14
docs/man/clamd.conf.5.in
View file

@ -245,10 +245,16 @@ Enable non-blocking (multi-threaded/concurrent) database reloads. This feature w
Default: yes
.TP
\fBVirusEvent COMMAND\fR
Execute a command when a virus is found. In the command string %v will be
replaced with the virus name and %f will be replaced with the file name.
Additionally, two environment variables will be defined: $CLAM_VIRUSEVENT_FILENAME
and $CLAM_VIRUSEVENT_VIRUSNAME.
Execute a command when virus is found.
Use the following environment variables to identify the file and virus names:
- $CLAM_VIRUSEVENT_FILENAME
- $CLAM_VIRUSEVENT_VIRUSNAME
In the command string, '%v' will also be replaced with the virus name.
Note: The '%f' filename format character has been disabled and will no longer
be replaced with the file name, due to command injection security concerns.
Use the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead.
For the same reason, you should NOT use the environment variables in the
command directly, but should use it carefully from your executed script.
\fR
.br
Default: disabled

16
etc/clamd.conf.sample
View file

@ -215,12 +215,18 @@ Example
# Default: yes
#ConcurrentDatabaseReload no
# Execute a command when virus is found. In the command string %v will
# be replaced with the virus name and %f will be replaced with the file name.
# Additionally, two environment variables will be defined: $CLAM_VIRUSEVENT_FILENAME
# and $CLAM_VIRUSEVENT_VIRUSNAME.
# Execute a command when virus is found.
# Use the following environment variables to identify the file and virus names:
# - $CLAM_VIRUSEVENT_FILENAME
# - $CLAM_VIRUSEVENT_VIRUSNAME
# In the command string, '%v' will also be replaced with the virus name.
# Note: The '%f' filename format character has been disabled and will no longer
# be replaced with the file name, due to command injection security concerns.
# Use the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead.
# For the same reason, you should NOT use the environment variables in the
# command directly, but should use it carefully from your executed script.
# Default: no
#VirusEvent /usr/local/bin/send_sms 123456789 "VIRUS ALERT: %v in %f"
#VirusEvent /opt/send_virus_alert_sms.sh
# Run as another user (clamd must be started by root for this option to work)
# Default: don't drop privileges

16
win32/conf_examples/clamd.conf.sample
View file

@ -187,12 +187,18 @@ TCPAddr localhost
# Default: yes
#ConcurrentDatabaseReload no
# Execute a command when virus is found. In the command string %v will
# be replaced with the virus name and %f will be replaced with the file name.
# Additionally, two environment variables will be defined: $CLAM_VIRUSEVENT_FILENAME
# and $CLAM_VIRUSEVENT_VIRUSNAME.
# Execute a command when virus is found.
# Use the following environment variables to identify the file and virus names:
# - $CLAM_VIRUSEVENT_FILENAME
# - $CLAM_VIRUSEVENT_VIRUSNAME
# In the command string, '%v' will also be replaced with the virus name.
# Note: The '%f' filename format character has been disabled and will no longer
# be replaced with the file name, due to command injection security concerns.
# Use the 'CLAM_VIRUSEVENT_FILENAME' environment variable instead.
# For the same reason, you should NOT use the environment variables in the
# command directly, but should use it carefully from your executed script.
# Default: no
#VirusEvent "C:\example\SendEmail.ps1" email@addresscom "VIRUS ALERT: %v in %f"
#VirusEvent "C:\example\SendVirusAlertEmail.ps1"
# Run as another user (clamd must be started by root for this option to work)
# Default: don't drop privileges