False Positives in Safe PDF File Analysis about capev2 HOT 5 CLOSED

class RegistryCredentialStoreAccess(Signature):
    name = "registry_credential_store_access"
    description = "Accessed credential storage registry keys"
    severity = 3
    categories = ["persistence", "lateral", "credential_dumping"]
    authors = ["Kevin Ross"]
    minimum = "1.3"
    evented = True
    ttps = ["T1003"]  # MITRE v6,7,8
    ttps += ["T1003.002"]  # MITRE v7,8
    mbcs = ["OB0005"]

    def run(self):
        ret = False
        reg_indicators = [
            "HKEY_LOCAL_MACHINE\\\\SAM$",
            "HKEY_LOCAL_MACHINE\\\\SYSTEM$",
        ]

        for indicator in reg_indicators:
            match = self.check_key(pattern=indicator, regex=True)
            if match:
                self.data.append({"regkey": match})
                ret = True
        # Tweak
        if "PDF" in self.results["target"]["file"].get("type", ""):
            self.severity = 1
        return ret

from lib.cuckoo.common.abstracts import Signature

class PDF_Annot_URLs_Checker(Signature):
    name = "pdf_annot_urls_checker"
    description = "The PDF contains a Link Annotation"
    severity = 2  # Default severity
    categories = ["static"]
    authors = ["Wassime BATTA"]
    minimum = "0.5"

    filter_analysistypes = set(["file","static"])

    malicious_tlds_file = "/opt/CAPEv2/data/malicioustlds.txt"

    def __init__(self, *args, **kwargs):
        super(PDF_Annot_URLs_Checker, self).__init__(*args, **kwargs)
        self.malicious_tlds = self.load_malicious_tlds()

    def load_malicious_tlds(self):
        malicious_tlds = set()
        with open(self.malicious_tlds_file, "r") as f:
            for line in f:
                line = line.strip()
                if line.startswith("."):
                    malicious_tlds.add(line)
        return malicious_tlds

    def run(self):
        found_malicious_extension = False
        found_malicious_domain = False
        found_domain_only = False
        suspect = False

        if "PDF" in self.results["target"]["file"].get("type", ""):
            if "Annot_URLs" in self.results["target"]["file"]["pdf"]:
                for entry in self.results["target"]["file"]["pdf"]["Annot_URLs"]:
                    entry_lower = entry.lower()
                    self.data.append({"url": entry})
                    if entry_lower.endswith((".exe", ".php", ".bat", ".cmd", ".js", ".jse", ".vbs", ".vbe", ".ps1", ".psm1", ".sh")) \
                            and not entry_lower.startswith("mailto:"):
                        found_malicious_extension = True

                    if entry_lower.startswith("http://") or entry_lower.startswith("https://"):
                        domain_start = entry_lower.find("//") + 2
                        domain_end = entry_lower.find("/", domain_start)
                        if domain_end == -1:
                            domain = entry_lower[domain_start:]
                        else:
                            domain = entry_lower[domain_start:domain_end]

                        for malicious_tld in self.malicious_tlds:
                            if domain.endswith(malicious_tld):
                                found_malicious_domain = True
                                break
                        else:
                            # If no malicious TLDs detected, set found_domain_only to True
                            found_domain_only = True

            if found_malicious_domain or found_malicious_extension:
                self.severity = 6
                self.description = "The PDF contains a Malicious Link Annotation"
                suspect = True
            elif found_domain_only:
                self.severity = 2
                self.description = "The PDF contains a Link Annotation"
                suspect = True

        return suspect

.link
.cam
.bar
.surf
.xyz
.click
.buzz
.gq
.ga
.rest
.ml
.cc
.cfd
.cyou
.accountant
.ar
.bg
.bid
.biz
.biz.ua
.br
.camera
.cf
.club
.co
.co.ua
.co.in
.co.mz
.co.nz
.com.au
.com.tw
.computer
.cricket
.date
.diet
.download
.email
.es
.faith
.gdn
.global
.guru
.help
.in
.info
.kz
.lol
.loan
.media
.men
.news
.ninja
.nyc
.party
.photography
.pt
.pw
.racing
.reise
.review
.rocks
.ru
.science
.site
.solutions
.space
.stream
.tech
.today
.top
.tr
.trade
.uno
.us
.vn
.webcam
.website
.win
.work
.africa
.autos
.best
.bet
.bio
.boats
.bond
.boston
.boutique
.center
.charity
.christmas
.coupons
.dance
.finance
.fishing
.giving
.hair
.haus
.homes
.icu
.kim
.lat
.llp
.loans
.love
.ltd
.mom
.motorcycles
.name
.okinawa
.promo
.rehab
.rugby
.run
.sale
.sew
.skin
.store
.sz
.tattoo
.tokyo
.voto
.wang
.wf
.yachts
.you