Malicious PDF — malware analysis report

Static analysis result for SHA-256 7437c1dff67310b3…

MALICIOUS

PDF

74.6 KB Created: 2021-09-08 03:02:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: a6dcff01989aaad5105481422f79723f SHA-1: b8aff78a51bdaee869a8ce328c9d94d2ff14d837 SHA-256: 7437c1dff67310b393a14a7c1dd7e788d4ff761832fb037a15fbce5ff4cea193
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It functions as a link farm, containing numerous URLs pointing to other PDF files hosted on various websites, some of which appear to be compromised CMS upload directories. The presence of multiple unknown PDF links suggests an attempt to lure users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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 http://mg001.cn/upload_fck/file/2021-5-10/20210510085110241608.pdf In PDF document text
    • http://colorfusion.us/admin/images/file/62438285084.pdfIn PDF document text
    • http://tourbusan.net/FileData/ckfinder/files/20210619_7A62EF7B6226F3BA.pdfIn PDF document text
    • http://shangrilayunnan.com/ckfinder/userfiles/files/93921490204.pdfIn PDF document text
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c7b24cc7dbe---78399418257.pdfIn PDF document text
    • http://vaynhe.com/upload/files/wisigumiximusev.pdfIn PDF document text
    • https://ladychief.com/wp-content/plugins/super-forms/uploads/php/files/665658648e7709e1494de9d687c9ba60/diwixerate.pdfIn PDF document text
    • http://apluskleaning.com/admin/images/file/xibokagavafu.pdfIn PDF document text
    • http://mai-colle.jp/userfiles/file/rapalajiroxepor.pdfIn PDF document text
    • http://alpanelektrik.com/depo/sayfaresim/file/73358545626.pdfIn PDF document text
    • https://cabsfromheathrow.com/userfiles/file/tuvixot.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/ed0817006d3df6eeb878dc6b50428c22/popopapuwamudowuzanazu.pdfIn PDF document text
    • https://susta.vn/userfiles/file/gefizusiretot.pdfIn PDF document text
    • http://ebd.su/UFD/7623/files/42705447994.pdfIn PDF document text
    • https://ksdc.in/userfiles/file/bakajataguvu.pdfIn PDF document text
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/1608656860dd0c---lotinizasibirizepuwera.pdfIn PDF document text
    • http://domainecomps.com/documents/files/29239644484.pdfIn PDF document text
    • http://vce34.ru/attachments/file/renajon.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612b1256f2599---69913983005.pdfIn PDF document text
    • http://aliguoriarchitetto.eu/userfiles/files/904399223.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/abc63447bc96253514ae01ae5ea75b53/453624067.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=catalogo+mary+kay+marzo+2019+pdfPDF 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_off0000be3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE3D 17312 bytes
SHA-256: 12532a9e3681ed99dd9115f1e729a1b4a9e0c5f6e02aeffd7a5bd6bde87b1f34
font_01_sfnt_off0000eb1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB1F 11104 bytes
SHA-256: 14532e2500e9465edc1688c256e9f1281f6bf5c79be6f1d00f21670f0e625ca2
font_02_sfnt_off0001050c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1050C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1