Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4844f5c87143b28…

MALICIOUS

PDF

69.3 KB Created: 2021-09-28 20:35:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: c923a978a200a77d9baa8dbd7a3abe02 SHA-1: 8d63b4afc194fc0fcb106886eecbfdd87f9544a5 SHA-256: a4844f5c87143b28528cd389c70e868c25cec5eda7d920c4a0bb993cc9d67301
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs pointing to various domains, many of which appear to be disposable hosting or compromised CMS uploads. Heuristics indicate this is a link farm, likely for SEO manipulation or to host malicious content. ClamAV detection as 'Pdf.Phishing.Trojan' further supports a malicious classification.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://archism.ru/uplcv?utm_term=2nd+puc+biology+textbook+pdf+english+medium PDF link annotation
    • http://konditsionery-zheleznodorozhnyi.ru/upload_picture/file/genezifixelos.pdfIn PDF document text
    • http://hocomesun.com/upload/xuzusuwedeka.pdfIn PDF document text
    • http://www.armstrongre.com/files/files/zapawasoxarok.pdfIn PDF document text
    • https://mytekas.com/UserFiles/file/xunofenew.pdfIn PDF document text
    • https://asiarsolutions.com/userfiles/file/bogeperuxapitoxodem.pdfIn PDF document text
    • http://ecohost.ru/pics/images/file/35861322156.pdfIn PDF document text
    • https://incoyun.com/calisma2/files/uploads/90916872840.pdfIn PDF document text
    • http://patrickstaxi.fr/userfiles/file/77307424393.pdfIn PDF document text
    • http://finsura-lifedirect.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16144e41793a15---10715232220.pdfIn PDF document text
    • https://dortmundpools.com/contents/files/54966156997.pdfIn PDF document text
    • http://teakdeck.pl/files/file/76450482368.pdfIn PDF document text
    • http://a-pluset.com/userfiles/feronomiz.pdfIn PDF document text
    • http://www.rlktechniek.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613c7804f1bc8---tefujididenalelepa.pdfIn PDF document text
    • http://chieusangducphat.com/uploads/userfiles/file/15283134051.pdfIn PDF document text
    • http://www.niceresidence.net/image/upload/File/86630379242.pdfIn PDF document text
    • https://urology-andrology.com/userfiles/file/75657717004.pdfIn PDF document text
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/rqqrhmaqoump2mc64umari1oc5/meveviladusatipezikotozam.pdfIn PDF document text
    • http://ciccioinpentola.com/userfiles/files/pudemutebubadugirijes.pdfIn PDF document text
    • http://rootbeadmill.com/upload_fck/file/2021-9-7/20210907073154492631.pdfIn PDF document text
    • http://vidol.nl/userfiles/file/19404637384.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d945611e37---gamenazimalenetawa.pdfIn PDF document text
    • https://www.xtremefitness.com.au/application/third_party/ckfinder/userfiles/files/3887585960.pdfIn PDF document text
    • http://murzilka.biz/images/uploads/file/55520854697.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000afc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAFC3 16616 bytes
SHA-256: 61397502d50c879bbb20c3ef88aba3b749f0fe8222bf6e5442eeebb543ecfbf1
font_01_sfnt_off0000da63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA63 11376 bytes
SHA-256: 19fb56a63f2292580cfbad0bb28d307a17596c9266a8e58bf9100bddf43991d4
font_02_sfnt_off0000f4a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4A6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1