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Fencer Intel
high 7.5

GHSA-hhjv-jq77-cmvx json

zeptoclaw has Android device shell blocklist bypass via argument permutation

published 8mo ago modified 8mo ago

cvss
7.5
version 3.1, GitHub
cisa kev
Not listed
not in CISA's catalog
epss
—
no score, EPSS covers CVEs only
public exploits
0
none known

Summary

### Summary [zeptoclaw](https://github.com/qhkm/zeptoclaw) implements a [blocklist](https://github.com/qhkm/zeptoclaw/blob/fe2ef07cfec5bb46b42cdd65f52b9230c03e9270/src/tools/android/actions.rs#L413-L424) to prevent dangerous commands running in android device shell, but this blocklist has several blocked commands with argements in the pattern literal, such as `rm -f` and `rm -rf`, this can be simply bypassed by using different orders for these arguments, such as `rm -r -f` or `rm -fr` etc.

### Details As in code [src/tools/android/actions.rs#L413-L424](https://github.com/qhkm/zeptoclaw/blob/fe2ef07cfec5bb46b42cdd65f52b9230c03e9270/src/tools/android/actions.rs#L413-L424), we can see the `rm -f` and `rm -rf` are hard coded and thus can be simply bypassed via `rm -r -f` or `rm -fr` etc. ```rust pub async fn device_shell(adb: &AdbExecutor, cmd: &str) -> Result<String> { // Normalize whitespace for blocklist check let normalized: String = cmd.split_whitespace().collect::<Vec<_>>().join(" "); let lower = normalized.to_lowercase();

let blocked = [ "rm -rf", "rm -r", "reboot", "factory_reset", "wipe", "format", "dd if=", "mkfs", "flash", "fastboot", ]; for pattern in &blocked { if lower.contains(pattern) { return Err(ZeptoError::Tool(format!( "Blocked dangerous command containing '{}'", pattern ))); } } ```

### PoC Set up [zeptoclaw](https://github.com/qhkm/zeptoclaw) with an Android tool and then run the command `rm -f -r` etc.

### Impact Unauthorized command executed in Android device.

### Credit [@zpbrent](https://github.com/zpbrent)

Patch / fix

  • crates.io zeptoclaw 0.6.2

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CVSS scores

assigned by version score vector
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io zeptoclaw
<0.6.2
0.6.2

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

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