Malicious PDF — malware analysis report

Static analysis result for SHA-256 861b428b239cde92…

MALICIOUS

PDF

77.7 KB Created: 2021-09-19 17:18:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 553aafd03c713652810eee2fc81b163e SHA-1: b291f548f23e8d5ce818feabefd91866ded509d4 SHA-256: 861b428b239cde92196b386f8c95921ae31d69833cab1cccd481d3e80d2cbb06
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm on disposable hosting, with multiple links pointing to compromised CMS uploads and potentially malicious PDFs. The embedded URLs suggest an attempt to direct users to external, untrusted sites, consistent with phishing or malware distribution tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://xn--o79av69abka850ab6c.com/upload/file/202109170403084790.pdf In PDF document text
    • http://mgbig.com/upload_fck/file/2021-9-19/20210919175554759864.pdfIn PDF document text
    • https://barrier.exma.cl/ckfinder/userfiles/files/powefidupepekoraxidas.pdfIn PDF document text
    • http://limoride.net/gallery/file/15124944502.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/2490869ca80fe8db02a392f689e8afb1/20474970789.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/ad7920adf72d652e64243c0404a1461f/15389300433.pdfIn PDF document text
    • http://gomsuhoangminh.com/app/webroot/uploads/files/14028911194.pdfIn PDF document text
    • http://maychamsocda.vn/images/userfiles/file/25877700229.pdfIn PDF document text
    • http://h-st.nl/bestanden/files/selojego.pdfIn PDF document text
    • http://effektfilm.de/files/file/fivukuxolaxar.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/b366dd0dec41d7173eeac7abce1e8fc8/69304470017.pdfIn PDF document text
    • http://eros-arena-reutlingen.de/eros/userfiles/file/40679041391.pdfIn PDF document text
    • http://kientrucphatloc.com/upload/files/bosularaselodabux.pdfIn PDF document text
    • http://intersonik.eu/upload/files/wewivilur.pdfIn PDF document text
    • https://clifestyle.net/uploades/userfiles/file/87586027828.pdfIn PDF document text
    • https://www.autopsrus.com/ckfinder/userfiles/files/49752624016.pdfIn PDF document text
    • http://victoryelectricalsupply.com/ckfinder/userfiles/files/sitevotovinixonebifepuwi.pdfIn PDF document text
    • https://terracell.pt/images/file/firerikurixodajoreb.pdfIn PDF document text
    • https://lifesmart.lifesmart.ro/ckfinder/userfiles/files/69834789173.pdfIn PDF document text
    • https://lordoptika.hu/files/files/fakebowudafoduxe.pdfIn PDF document text
    • http://hybsch.it/upload/file/51221467505.pdfIn PDF document text
    • https://sowlindia.com/userfiles/file/89431210726.pdfIn PDF document text
    • http://jenistudio.com/upload/FCK/file/385881431.pdfIn PDF document text
    • https://il-gusto.com/images/file/voravamabusojaboxolafodi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+root+android+applicationsPDF link annotation
    • 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://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/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_off0000cbd7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBD7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e3ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3EE 10452 bytes
SHA-256: fc04dfe9b7c55e2b27138571166bb964be018be12973c9ee88a1fa0bca33414d
font_02_sfnt_off0000fbbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBBF 17488 bytes
SHA-256: 5a17af708a5796dc91e108e53f9f6c47413489ed7dad7e7dc854515c6887e676