libffmpeg.change_decrease.mdiff

## Changed (0 added, 22 removed): macOS/2023.3CX/libffmpeg.dylib [😈 CRITICAL → 🟡 MEDIUM]

### 22 removed behaviors

| RISK | KEY | DESCRIPTION | EVIDENCE |
|--|--|--|--|
| -CRITICAL | [3P/sekoia/downloader_smooth_operator](https://github.com/SEKOIA-IO/Community/blob/e00b1ef08f974e483260719ce04b78fa8b79ee56/yara_rules/downloader_mac_smooth_operator.yar#L1-L16) | Detect the Smooth_Operator malware, by [Sekoia.io](https://github.com/SEKOIA-IO/Community) | [%s/.main_storage](https://github.com/search?q=%25s%2F.main_storage&type=code)<br>[%s/UpdateAgent](https://github.com/search?q=%25s%2FUpdateAgent&type=code) |
| -CRITICAL | [3P/sig_base/3cxdesktopapp_backdoor](https://github.com/Neo23x0/signature-base/blob/9d07a3bad717d5822fe6d9adaa4cffc871f397dd/yara/gen_mal_3cx_compromise_mar23.yar#L251-L275) | [Detects 3CXDesktopApp MacOS Backdoor component](https://www.volexity.com/blog/2023/03/30/3cx-supply-chain-compromise-leads-to-iconic-incident/), by X__Junior (Nextron Systems) | [%s/.main_storage](https://github.com/search?q=%25s%2F.main_storage&type=code)<br>[%s/UpdateAgent](https://github.com/search?q=%25s%2FUpdateAgent&type=code)<br>`$sa1`<br>`$sa2`<br>`$op1`<br>`$op2` |
| -CRITICAL | [3P/sig_base/nk_3cx_dylib](https://github.com/Neo23x0/signature-base/blob/9d07a3bad717d5822fe6d9adaa4cffc871f397dd/yara/gen_mal_3cx_compromise_mar23.yar#L188-L214) | [Detects malicious DYLIB files related to 3CX compromise](https://www.sentinelone.com/blog/smoothoperator-ongoing-campaign-trojanizes-3cx-software-in-software-supply-chain-attack/), by Florian Roth (Nextron Systems) | `$xc1`<br>`$xc2`<br>`$xc3` |
| -CRITICAL | [3P/sig_base/susp_xored_mozilla](https://github.com/Neo23x0/signature-base/blob/9d07a3bad717d5822fe6d9adaa4cffc871f397dd/yara/gen_xor_hunting.yar#L2-L25) | [Detects suspicious single byte XORed keyword 'Mozilla/5.0' - it uses yara's XOR modifier and therefore cannot print the XOR key](https://gchq.github.io/CyberChef/#recipe=XOR_Brute_Force()), by Florian Roth | `$xof1`<br>`$fpa1`<br>`$fpa2`<br>`$fpb1`<br>`$xo1` |
| -CRITICAL | [3P/volexity/iconic](https://github.com/volexity/threat-intel/blob/2df1665d51ea9560af4b36d2ae21926798b2e0f9/2023/2023-03-30%203CX/indicators/rules.yar#L32-L50) | [Detects the MACOS version of the ICONIC loader.](https://www.reddit.com/r/crowdstrike/comments/125r3uu/20230329_situational_awareness_crowdstrike/), by threatintel@volexity.com | `$str1`<br>`$str2`<br>`$str3` |
| -CRITICAL | [anti-static/xor/user_agent](https://github.com/chainguard-dev/malcontent/blob/main/rules/anti-static/xor/xor-user_agent.yara#xor_mozilla) | XOR'ed user agent, often found in backdoors, by Florian Roth | [xor_mozilla::$Mozilla_5_0](https://github.com/search?q=xor_mozilla%3A%3A%24Mozilla_5_0&type=code) |
| -CRITICAL | [impact/remote_access/net_exec](https://github.com/chainguard-dev/malcontent/blob/main/rules/impact/remote_access/net_exec.yara#lazarus_darwin_nsurl) | executes programs, sets permissions, sleeps, makes HTTP requests | [NSMutableURLRequest](https://github.com/search?q=NSMutableURLRequest&type=code)<br>[gethostname](https://github.com/search?q=gethostname&type=code)<br>[localtime](https://github.com/search?q=localtime&type=code)<br>[strncpy](https://github.com/search?q=strncpy&type=code)<br>[sprintf](https://github.com/search?q=sprintf&type=code)<br>[pclose](https://github.com/search?q=pclose&type=code)<br>[flock](https://github.com/search?q=flock&type=code)<br>[sleep](https://github.com/search?q=sleep&type=code)<br>[chmod](https://github.com/search?q=chmod&type=code)<br>[popen](https://github.com/search?q=popen&type=code)<br>[rand](https://github.com/search?q=rand&type=code) |
| -HIGH | [exec/shell/arbitrary_command_dev_null](https://github.com/chainguard-dev/malcontent/blob/main/rules/exec/shell/arbitrary_command-dev_null.yara#cmd_dev_null_quoted) | runs quoted templated commands, discards output | ["%s" >/dev/null](https://github.com/search?q=%22%25s%22+%3E%2Fdev%2Fnull&type=code) |
| -MEDIUM | [evasion/file/prefix](https://github.com/chainguard-dev/malcontent/blob/main/rules/evasion/file/prefix/prefix.yara#dynamic_hidden_path) | [hidden path generated dynamically](https://objective-see.org/blog/blog_0x73.html) | [%s/.main_storage](https://github.com/search?q=%25s%2F.main_storage&type=code) |
| -MEDIUM | [exec/cmd/pipe](https://github.com/chainguard-dev/malcontent/blob/main/rules/exec/cmd/pipe.yara#popen) | [launches program and reads its output](https://linux.die.net/man/3/popen) | [_pclose](https://github.com/search?q=_pclose&type=code)<br>[_popen](https://github.com/search?q=_popen&type=code) |
| -MEDIUM | [fs/permission/modify](https://github.com/chainguard-dev/malcontent/blob/main/rules/fs/permission/permission-modify.yara#chmod) | [modifies file permissions](https://linux.die.net/man/1/chmod) | [chmod](https://github.com/search?q=chmod&type=code) |
| -MEDIUM | [net/http/accept](https://github.com/chainguard-dev/malcontent/blob/main/rules/net/http/accept.yara#http_accept_binary) | accepts binary files via HTTP | [application/octet-stream](https://github.com/search?q=application%2Foctet-stream&type=code)<br>[Accept](https://github.com/search?q=Accept&type=code) |
| -MEDIUM | [net/http/cookies](https://github.com/chainguard-dev/malcontent/blob/main/rules/net/http/cookies.yara#http_cookie) | [access HTTP resources using cookies](https://developer.mozilla.org/en-US/docs/Web/HTTP/Cookies) | [Cookie](https://github.com/search?q=Cookie&type=code)<br>[HTTP](https://github.com/search?q=HTTP&type=code) |
| -MEDIUM | [net/url/request](https://github.com/chainguard-dev/malcontent/blob/main/rules/net/url/request.yara#requests_urls) | requests resources via URL | [NSMutableURLRequest](https://github.com/search?q=NSMutableURLRequest&type=code) |
| -LOW | [data/compression/gzip](https://github.com/chainguard-dev/malcontent/blob/main/rules/data/compression/gzip.yara#gzip) | [works with gzip files](https://www.gnu.org/software/gzip/) | [gzip](https://github.com/search?q=gzip&type=code) |
| -LOW | [data/random/insecure](https://github.com/chainguard-dev/malcontent/blob/main/rules/data/random/insecure.yara#bsd_rand) | [generate random numbers insecurely](https://man.openbsd.org/rand) | [_rand](https://github.com/search?q=_rand&type=code)<br>[srand](https://github.com/search?q=srand&type=code) |
| -LOW | [discover/system/hostname](https://github.com/chainguard-dev/malcontent/blob/main/rules/discover/system/hostname.yara#gethostname) | [get computer host name](https://man7.org/linux/man-pages/man2/sethostname.2.html) | [gethostname](https://github.com/search?q=gethostname&type=code) |
| -LOW | [discover/user/HOME](https://github.com/chainguard-dev/malcontent/blob/main/rules/discover/user/HOME.yara#HOME) | [Looks up the HOME directory for the current user](https://man.openbsd.org/login.1#ENVIRONMENT) | [getenv](https://github.com/search?q=getenv&type=code)<br>[HOME](https://github.com/search?q=HOME&type=code) |
| -LOW | [fs/lock_update](https://github.com/chainguard-dev/malcontent/blob/main/rules/fs/lock-update.yara#flock) | apply or remove an advisory lock on a file | [flock](https://github.com/search?q=flock&type=code) |
| -LOW | [net/http/accept_encoding](https://github.com/chainguard-dev/malcontent/blob/main/rules/net/http/accept-encoding.yara#content_type) | [set HTTP response encoding format (example: gzip)](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Encoding) | [Accept-Encoding](https://github.com/search?q=Accept-Encoding&type=code) |
| -LOW | [os/kernel/dispatch_semaphore](https://github.com/chainguard-dev/malcontent/blob/main/rules/os/kernel/dispatch-semaphore.yara#dispatch_sem) | [Uses Dispatch Semaphores](https://developer.apple.com/documentation/dispatch/dispatch_semaphore) | [dispatch_semaphore_signal](https://github.com/search?q=dispatch_semaphore_signal&type=code) |
| -LOW | [os/sync/semaphore_user](https://github.com/chainguard-dev/malcontent/blob/main/rules/os/sync/semaphore-user.yara#semaphore_user) | uses semaphores to synchronize data between processes or threads | [semaphore_create](https://github.com/search?q=semaphore_create&type=code)<br>[semaphore_signal](https://github.com/search?q=semaphore_signal&type=code)<br>[semaphore_wait](https://github.com/search?q=semaphore_wait&type=code) |