Malicious PDF — malware analysis report

Static analysis result for SHA-256 26a25bd464dacc8d…

MALICIOUS

PDF

95.5 KB Created: 2021-05-30 04:20:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 90bd47fa0ff8a19b0b27bdee628c0ff0 SHA-1: da84d59ba243e047ba96083067aad1215cb27ea3 SHA-256: 26a25bd464dacc8d78de77b539263d61f063e7674b05ac4fd7b2946db1316d58
186 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO manipulation tactic. One of the primary links, 'https://resalured.ru/strik?utm_term=photosynthesis+diagram+worksheet+pdf+answers', suggests a lure related to educational content, likely to trick users into clicking through to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://resalured.ru/strik?utm_term=photosynthesis+diagram+worksheet+pdf+answers PDF link annotation
    • https://piminuwimizo.weebly.com/uploads/1/3/4/6/134674326/6633552.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378599/normal_6033163f55dea.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451363/normal_5fd102ba7a637.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4493579/normal_60610c9e31d20.pdfIn PDF document text
    • https://fegikunula.weebly.com/uploads/1/3/4/4/134482285/e53d54d782fb3.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4409114/normal_5fe5a199020bc.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421640/normal_6067bad834b98.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368975/normal_6018a18f54e8c.pdfIn PDF document text
    • https://mabaxezo.weebly.com/uploads/1/3/4/7/134766945/gepib_vavegezusodasaj.pdfIn PDF document text
    • https://zegarujavo.weebly.com/uploads/1/3/4/6/134667802/bewixiluja-bubowaxulavu-vefitagilubojet-debaxoz.pdfIn PDF document text
    • https://bitusuverutito.weebly.com/uploads/1/3/1/8/131871453/5e541daa9b46225.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4460686/normal_5fe65024de8d5.pdfIn PDF document text
    • https://siwetoro.weebly.com/uploads/1/3/0/8/130814297/5358969.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446633/normal_5ff3a1356f1da.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370987/normal_603a5fb9cd173.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378425/normal_600ef6fc6ce1c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403556/normal_600e286f68bcd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423700/normal_603327b3ee219.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483338/normal_605974e86450e.pdfIn PDF document text
    • https://gifaxefapi.weebly.com/uploads/1/3/4/5/134598377/3440811.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483388/normal_602f56bec0ae2.pdfIn PDF document text
    • https://barurusijibipek.weebly.com/uploads/1/3/0/7/130740419/56f3b6.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4369504/normal_5fe4cffd6e504.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn 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_off00011e21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E21 5684 bytes
SHA-256: f2b1c3e3182d624753de5bef93bb0e3fe218d6b6ed0906cabec82bf5301a8170
font_01_sfnt_off0001316e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1316E 12284 bytes
SHA-256: 856e225a863dd293d73fc9fdb637a57f8f28f6dcd09391192c29340a93aa26b0
font_02_sfnt_off00015ac9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15AC9 16204 bytes
SHA-256: 532315dfdc59b350d447ad91845dd8cc72a836e684f536ab9a4305dc5b53fb8e