Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c771f1679650936…

MALICIOUS

PDF

71.7 KB Created: 2021-10-08 06:18:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: ff6a03e2524f199500ece07b042fb26d SHA-1: f8cd7665aadee6613d6459c013b19d5cc91a45ab SHA-256: 4c771f1679650936bd215f1519d3a3a84a18e191c57ca8b0909be580df01e16d
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. The presence of external URI heuristics and link farm indicators supports the conclusion that this document is intended to lead users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://catamma.ru/uplcv?utm_term=rrb+exam+model+paper+in+english PDF link annotation
    • http://russia-ex.com/images/blog/file/fonukujatekafetav.pdfIn PDF document text
    • http://romanasulcikova.cz/userfiles/49340772993.pdfIn PDF document text
    • https://bepcongnghiepphuchung.vn/userfiles/file/50254933999.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/8cb6dd9b0fee793e1f904c4274945a0a/24521154107.pdfIn PDF document text
    • https://hkki.org/userfiles/files/54734749548.pdfIn PDF document text
    • https://projectmine.hu/ckfinder/userfiles/files/widuvilokurev.pdfIn PDF document text
    • http://jianianhuayule.a9188.com/upload_files/art_files/files/20210910_221105.pdfIn PDF document text
    • http://maytinhnangdong.com/files/uploads/editor/files/92618380637.pdfIn PDF document text
    • http://28777886.com/Lpf/UPFILE/userfiles/files/ziluzisixobafebob.pdfIn PDF document text
    • http://kaitianjinghua.cn/admin/userfiles/file/202109191104269863.pdfIn PDF document text
    • https://apexforestservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/161478511142bc---salojotarinubelobe.pdfIn PDF document text
    • http://dietetyka-24.pl/images/files/tibuzezitadanegaf.pdfIn PDF document text
    • https://bistro-8.com/wp-content/plugins/super-forms/uploads/php/files/02bc1bdc8cff9478a7ffcde3650bbd8b/fekesiteg.pdfIn PDF document text
    • http://sirindhorn.net/upload/File/3217340235.pdfIn PDF document text
    • https://alshuka.ps/ckfinder/userfiles/files/razevubifodozowosobim.pdfIn PDF document text
    • https://al-farh-iq.com/upload/userfiles/file/lulirilurasi.pdfIn PDF document text
    • https://phatgiaolongan.com/upload/ckupload/files/13549071190.pdfIn PDF document text
    • https://118highschool.am/wp-content/plugins/super-forms/uploads/php/files/7775654c1091688cc08986669dcf309e/21744529671.pdfIn PDF document text
    • http://cke.hk/userfiles/pikesipurevafinomotu.pdfIn PDF document text
    • https://balajihighfields.in/userfiles/file/jasasujipa.pdfIn PDF document text
    • http://gsoam.ge/wp-content/plugins/formcraft/file-upload/server/content/files/1613f80c017b37---kijanumudunu.pdfIn PDF document text
    • https://parvazyab.com/basefile/api203/files/49976190627.pdfIn PDF document text
    • https://szabobuszberles.hu/files/files/buxotojixoxujuzesu.pdfIn PDF document text
    • https://empresa-venta.hr/files/jowuve.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://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_off0000b378.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB378 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cb8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB8A 16616 bytes
SHA-256: df164fd7a5b56aa82fabf13b09e20294405f59310fccdef205b003043df52f43
font_02_sfnt_off0000f68a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF68A 11028 bytes
SHA-256: 890d16cd84b242b85dcd902cfa14e9385fa4778acbb0cf476f0e40f96901eff8